The South China Karst is a region of extraordinary topography - a land defined by limestone crags, seemingly otherworldly in their gravity-defying composition. The karst may be nothing more than a product of several millennia of limestone dissolution, but it's easy to grow misty-eyed when confronted with this natural spectacle.

Historically, this area, which spans the provinces of Guangxi, Guizhou and Yunnan, was a hotbed of ethnic insurrection and separatist movements. The region proved so difficult to pacify that the Chinese have long dubbed it "the land of a hundred barbarians" and even today, ethic minorities, as well as local Han, eke out lives as removed from mainstream affairs as one can be in today's China.

In a remote corner of karst country, the Bama Yao autonomous county has risen to prominence in recent years. The Bama Longevity Village is the county's hot ticket, due in no small part to the disproportionate number of centenarians living there. The native Zhuang and Yao all claim a family member who is at least 100 years old, with the eldest villager, Huang Xinbo, having chalked up 118 years, if all is to be believed.

Busloads of health-conscious pilgrims descend upon Bama from around the nation. In Poyue, a market town near Bama Longevity Village, holistic holidaymakers can be found bartering over exotic mountain fungi or glugging down "river of life" water - when viewed from the hills, one of Bama's principal waterways looks the calligraphic version of the character " ming", meaning "life". Yet despite the new timeshare apartments erected to accommodate the sick and elderly, bucolic Bama county is largely untouched, especially when compared with other Chinese tourist destinations.

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"They're just bussing in Cantonese grannies to buy herbal remedies for their colds, that's it!" as my host, Stephen Cramb, puts it.

As the only non-Chinese resident in Bama, Australian Cramb and his wife, Hongkonger Jessica Kong Yue-wan, represent true minorities among the minorities. Over Iron Buddha tea and fresh fruit in their guesthouse - the homely Bama Farmhouse Retreat - I ask the obvious: how did they become the first foreign hoteliers in Bama?

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"It's kind of a long story," explains Cramb, in an accent tinged with rural Queensland. "Like most kids growing up in Australia in the 1970s, I watched a lot of kung fu flicks. So I moved to Hong Kong in 1983, to study martial arts, and ended up staying."

According to Cramb, he lived through Hong Kong's "good old days", when rent was affordable and there were plenty of opportunities for adaptable expats. While working in a variety of professions, Cramb mastered Cantonese and earned his kung fu chops.

"I studied hung gar under Chiu Wai and his son, Dennis Chiu, and wing chun under Wong Shun-leung and Gary Lam, later learning Yang-style tai chi from Wong Ping-kwong."

Cramb ventured to China to study kung fu at the Shaolin Monastery and Wudang Mountain and would go on to win a dozen medals at international and national levels. In 1987, he married his Cantonese sweetheart, who remains the yang to his yin.

"I met Stephen in a disco in TST [Tsim Sha Tsui] in the '80s," says Kong, who grew up in Kwun Tong, an industrial district of Kowloon. "I was working at reception, he was a bouncer. I just noticed he had good energy and was hard-working."

After 18 years in Hong Kong, the Crambs, with two young daughters in tow, relocated to Australia, where they bought a four-hectare farm near Brisbane.

"Our youngest daughter was suffering asthma attacks in Hong Kong so we elected to move back to Queensland. From 2003 to 2010, much of the country was suffering from drought. The farm property was on sandy land so we couldn't grow many vegetables but we raised chickens and goats."

Life may have been tough but the family got by. However, nothing could prepare them for 2010, when "storms of the century" submerged much of Queensland and New South Wales, displacing 200,000 people.

Tossing his dreadlocks over his shoulder, Cramb gulps before recalling a calamity of near Biblical proportions.

"The Brisbane River ripped right through our district at Wivenhoe Pocket. I left before the river burst its banks and stayed in Brisbane for two weeks before I could return to the farm. Devastated, I walked away. The banks got the farm and we returned to China."

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The Crambs first went to Yangshuo, a tourist town on the Li River, establishing The Stone Bridge guest house in 2011.

"We were living in Master Fu [Nengbin's] Tai Chi School. We originally planned to help him expand but ended up building our own guest house nearby. We operated until 2014 then sold it. It was a thriving hostel but Yangshuo is a crazy and increasingly expensive place to do business. At our age, you think more about lifestyle. We learned of Bama and decided to move out here."

The Farmhouse Retreat is, by Cramb's own admission, a humble affair, designed to be "just like the locals live, but with softer beds and better food". It is situated on a ridge overlooking a stunning valley of farmland framed by forested mountains.

"Even if they develop tourism [in Bama], nobody is going to encroach on this view," says Cramb, who has taken out a 20-year-lease on the property. He has clearly put a great deal of work into his garden.

"It's more like a piece of art than a garden," he says, pointing to the shape of his vegetable patch, which curves and winds, invoking Taoist notions of flowing water. Cramb has found antique farm tools and refurbished them as garden ornaments. "People just throw these things out."

We stroll around the duck paddock, with Cramb describing excitedly how "everything gets used or reused", including the birds' faeces, as fertiliser.

Referring to himself as an "old hippie", Cramb seeks to make the garden sustainable. He's a genuine horticulturalist with an encyclopaedic knowledge of plants and animals, and hundreds of ideas about how to avoid using chemical fertilisers and insect repellents.

"Here, I'm putting lime dust on the cabbages to scare off the slugs," he says. "And come look at my chickens, how healthy they are. You don't need hormones. Plants and animals need good environments. If the basic conditions aren't right to start with, you'll have problems. The animals we raise are all well cared for and so are the garden beds; we feed the soil rather than fertilising the plants, and I am constantly recycling, composting to make new organic conditioners to improve the quality of the soil."

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Cramb's eco-ethics seem to fit neatly with Bama's reputation as an environmentally untarnished arcadia. Yet while he credits "the high mineral content in the water and soil, fresh air and traditional lifestyles" for the health of Bama's natives, he perceives failings with local farm practices.

"I believe a lot of corn in the area may be GMO [genetically modified organisms] so we refuse to touch it. The locals don't know about GMO, they don't know about poison and ground toxicity, they are simple slash-and-burn farmers, they plant and hope for the best and waste money on fertilisers. I spend no money yet I can create very fertile soil, for free, paid for simply by my effort."

Cramb is also a self-taught mechanic and has spent the last year fixing up three motorbikes.

"It's great, I ride around with no helmet discovering caves and new places to swim. It's like being a kid again."

Following cautiously in a motor-rickshaw with Kong, I see the sights of the area, including Landing, an isolated Yao minority village; Sanmenhai, where an underground river passes through caves; and Yin and Yang Mountain, so called because the twin hills appear to represent male and female genitalia.

"This is my favourite spot," says Kong, letting loose with her infectious laugh.

"I don't think too much about what will or might be. I just try to enjoy the moment. Business is good and Bama has a nice rhythm. We can go anywhere and do whatever we want to do; it's free here," she says.

"Bama is like Yangshuo 20 years ago," says Cramb. "There's just so much potential here. Climbing these stunning cliffs, caving through amazing tunnels or canoeing down the Panyang River, this place just needs the right people to make it happen. I plan to invite some Yangshuo climbers to come up and survey the area."

Located on the northeast fringe of the Guangxi Zhuang autonomous region, several hours east of Bama, Yangshuo is a far more accessible karst town. Guilin city, which administers Yangshuo, has been a top tourist spot since the Song literati began waxing lyrical about it 1,000 years ago. But whereas authorities groomed Guilin for tourists, Yangshuo's development was far more organic, beginning with a few itinerant travellers in the 1990s.

Epitomising an idealised China of farmers leading water buffalo through rice paddies (yet somewhere you could still get a good pizza and a pint of beer), Yangshuo soon earned itself the "backpacker mecca" epithet. But, inevitably, this foreigner-friendly hub attracted the attention of developers. When filmmaker Zhang Yimou established his Impression Liu Sanjie show on the Li River in 2003, he effectively opened the door for tour groups to pour in. A host of tawdry theme parks followed and Yangshuo's days as a peripheral destination for off-the-beaten-path travellers were numbered.

Today, those seeking something of the old vibe invariably head to Xingping, a township just 25km north of Yangshuo. Devoid of nightlife, Xingping has a gentler feel, despite the armada of riverboats that deposit happy-snapping sightseers to photograph the bend in the Li River that is depicted on the 20-yuan note.

Yet change is underway in Xingping, too. Old Street, once a place of wood and stone dwellings occupied by elderly locals, is turning into a tourist strip, with cafés and hostels mushrooming along it. Navigating the dust and chaos generally associated with Chinese construction, I find refuge in the Old Street Café, where I meet Belgian photographer Gregory Michiels, fiancé of café owner Leena Lin Hongmei.

Michiels had been something of a world wanderer before falling in love with this quarter of China, in 2008.

"I found China so different from the West, it totally fascinated me. Plus it's still not well promoted outside. You can still find a place to take a fresh picture."

A landscape photographer,  in 2012 Michiels established Another Day at the Office, a service catering to photography enthusiasts looking for local scenery at its finest.

"I've found all the best locations in Guilin," he boasts.

Walking down Old Street, I ask Michiels what he thinks of the changes taking place in Xingping.

"It's kind of tacky, they're using fake brick instead of old stone," he says. "But there's going to be a lot more tourists now that the high-speed train station is open. You know Yangshuo Station is actually in Xingping."

Surveying the panorama from Laozhai Mountain, you can see why photographers are attracted to Xingping. The hiking trails are little known and it is unquestionably stunning. But even at the summit of the mountain, change is in the air.

"They're building a five-star resort over there," Michiels says, pointing down to a river, before indicating further afield, "and behind that mountain, you'll find the new railway station".

After lunch, Michiels has to meet a client who wants to photograph the renowned Li River cormorant fishermen.

"There are just three people who still know how to fish with birds," Michiels explains. "Two of them are over 80."

He invites me along and we boat out to an islet on the river, where a fisherman dressed in traditional peasant garb poses with his birds and has fun pouting like a catwalk model. The photographers fire salvos from their Canons in his direction, all aiming to capture that definitive Li River shot.

While discussing the changes taking place in Xingping, Michiels suggests we visit Jiuxian, a village south of Yangshuo, on the banks of the Yulong River, where another foreigner is going against the grain, redeveloping a dilapidated village of crumbling Qing-era houses.

"You'll find some edginess there," he assures me.

We bus down to Yangshuo and rent bicycles - the best, perhaps the only, way to get to Jiuxian, which is situated far from any main road. As soon as we escape Yangshuo's many noisy, indistinguishable restaurants serving the local speciality, beer fish, we are returned to a paradise of farmers tending vegetable patches wedged between karst hills and the jade waters of the Yulong.

Jiuxian proves to be a small, mottled village with a few ancestral halls, dilapidated houses bearing ominous Cultural Revolution-era graffiti and, down a cobbled path, the Secret Garden Hotel.

Eight refurbished buildings in which the classical and new have been reconciled with exceptional sensitivity, Secret Garden is, as its name suggests, a clandestine realm that is quintessentially Chinese.

"I'm sorry, I have to get this ready, we have a booking here tomorrow," explains cheerful South African Ian Hamlinton, as he paints one of the rooms. "I'm trying not to work seven days a week but I've not been very successful."

Hamlinton, an architect by trade but someone who "can't sit in front of a computer all day", had, like Michiels, been something of a globetrotter, having worked in Egypt and India before coming to China.

"I arrived in 2001, working as tour leader for Imaginative Traveller, a British adventure tour company. I became assistant destination manager for the Far East in 2003 and my office was based in Yangshuo, so I started living here full time then.

"In 2003, there were still people who lived on West Street, there were a few cafés and hotels, but no bars. After Sars [the severe acute respiratory syndrome outbreak], it became really popular with Chinese tourists and the beer fish restaurants, nightclubs and shops selling tourist tat opened. It stopped being a 'fishing village', as the Lonely Planet then described it, and became the same as most other tourist destinations in China. People who owned property on West Street rented their homes out for increasingly ridiculous prices. My apartment faced east and, every morning, I woke up to the sun rising over the mountains reflecting off the Li River. But after five years, I struggled to get up with the sun since I couldn't sleep at night due to the constant noise of drunken patrons singing and shouting their way home."

Hamlinton moved on in search of authenticity and found Jiuxian in July 2009.

"I opened with six guest rooms in September 2011 and have expanded slowly," he explains.

I ask where Hamlinton finds his inspiration.

"I don't watch TV or follow the trends; I'm inspired by the buildings themselves," he says. "I try and look at the character of each house and then work out how to enhance this character and improve any areas that are lacking. I always seek to imagine what the original designers were trying to achieve and imagine how they would improve the buildings today based on the current materials available. I try to be honest by not making new things look old and I don't believe in disguising the building materials I've used."

The hotel is brimming with antiques, old wooden fixtures and trinkets. Where did they all come from?

"Everywhere I go I look for things that can be used in my buildings," he says. "When I visit friends in other places, I always try and stop at markets and hardware stores. I buy anything that inspires me without knowing how I will use it and usually find a perfect use for everything at some point.

"I also try to reuse everything that I find in the buildings. I buy a lot of second-hand materials. Most of our stairs, tables and counters are made from old doors. I use a lot of old mud bricks from the village because they are free, good for the environment and remind me of my friends whenever I see a wall built from part of their house.

"I love everything to have a story."

Secret Garden's café has a compelling layout, with a marvellous use of space that climbs upwards over three levels, mirroring the hillside behind the village. At the top is the Tree House, from where diners can look out across the slate roofs of Jiuxian to the karst hills beyond. And, as one might expect for a place that straddles the old and new, East and West, the menu fuses Guilin specialities with Western staples.

After lunch, Hamlinton shows us his personal art gallery, where he exhibits his China-inspired paintings, and some of the vacant rooms in the property, all artfully decorated.

"When I arrived I didn't know if I could live here. I mean, where in the world could you move to a remote village and be so welcome? But [the villagers] invited me to weddings, celebrations and dinners and treated me so well. Of course, I do try to blend in."

To that end, Hamlinton says he never sneaks off to Yangshuo for a sandwich.

"No, I eat with the staff or the villagers. Tonight we're having rat, you're welcome to come along if you like."

We politely decline, and take our leave.

As Michiels puts it, as we pedal off, "Where else might Ian find such properties to work on at these kind of prices? In Europe, people like him dream of restoration projects like this.

"It's a once-in-a-lifetime opportunity."