Mustang has acquired a Shangri-La-like reputation because of the pervasive influence of Tibetan culture (it is known as "Tibet outside the Tibetan border") and the fact that it remained closed to foreigners until 1991.

After acclimatizing for a few days in the Kathmandu Valley, our journey began with a flight to Jomsom, a small town squeezed between the mountains in Nepal that boasts a tiny airport on the banks of the Kali Gandaki River. You need to book an early flight because, by late morning, high winds sweeping up the valley make conditions too dangerous for flying.

Just outside the airport gates, accompanied by our sidar (or guide), we met the cook, support staff and the small Tibetan ponies that would carry our gear. We quickly grew to rely on them for our well-being and enjoyed their camaraderie at our campsites over the next three weeks.

Our first day was spent walking directly up the river's flood plain. Where the river pierces the Himalaya, it creates the deepest gorge in the world, and we felt dwarfed by the immense cliffs on either side. In the village of Kagbeni, we were stopped at a police checkpoint to ensure that our permits were in order.

Gazing north, we could see dust devils swirling up the river bed, before disappearing into the restricted zone of Upper Mustang. This valley is part of a traditional route used to bring wool and salt down from Tibet in exchange for trade goods from Nepal and India. Virtually everything in Mustang arrives on the backs of pack animals and porters because there is no road access for motorized vehicles.

We followed the river's course for another day, then began climbing in a slow arc through a chain of isolated villages, where we would stop each night to pitch our tents.

We quickly learned to keep close to the mountain sides whenever we met caravans on the narrow trail. But it was hard not to be distracted by the awe-inspiring scenery: picture the Grand Canyon dropped onto the Tibetan plateau. One day, we trekked seven hours and ascended four passes, including the Syangboche La, at nearly 4,000 metres, an impossibly beautiful place marked by long strings of Buddhist prayer flags fluttering in the breeze. The views to the south were breathtaking, with the Annapurnas and Dhaulagiri, the seventh highest mountain in the world, soaring above the skyline, while to the north, our route was visible as a dusty scar etched across the arid hills sheltering Lo-Manthang.

Mustang's walled capital was built in the 14th century and is still entered through an enormous wooden gate, which used to be locked at night. It is truly medieval: a warren of narrow laneways that provide fleeting glimpses of a remarkable way of life. You may see a pilgrim spinning a Buddhist prayer wheel, saffron-robed monks deep in conversation, dung drying on a window sill to make fuel, or you may experience the shock of encountering a snarling Tibetan mastiff securely chained to a doorway.

During our visit, many of the townspeople were busy harvesting wheat and we squeezed past locals stooped under heavy sheaves. This crop, which is grown in small irrigated fields surrounding the town, is totally dependent on snowmelt and glacier runoff from the mountains.

As befits a town built in 1380, Lo-Manthang houses some remarkable antiquities. Jhampa Gompa (gompa means monastery) contains an enormous statue of "the Buddha yet to come" which, from our vantage point on a second-floor gallery, gazed at us impassively through dusty shafts of sunlight. Thupchen Gompa is decorated with extraordinary frescoes and murals, including a frightening deity draped in a skull necklace, which is being painstakingly restored by a team of Italian conservationists. Visitors are no longer allowed to take photos inside these shrines because art dealers were identifying relics from the photos and then commissioning thieves to steal the most valuable items. Nevertheless, such images leave an indelible impression, which the passage of time cannot erase.

We felt privileged to visit Lo-Manthang, because there is a sense that this area is on the threshold of great change. Evidence of Nepal's civil war -- such as the stenciled hammer-and-sickle emblems of the Maoists and signs advocating a "Himal Autonomous State" -- are giving way to advertisements for tea houses and solar-heated showers. Farther north, the Chinese are building a road down to the border, which will inevitably increase the number of visitors and, possibly, Mustang's reliance on its powerful northern neighbour. This has always been a sensitive area because Mustang was a refuge for Khampa tribesmen who fought against the Chinese occupation of Tibet and it remains one of the last outposts of traditional Tibetan culture.

We detected a resilience and strength, however, which encourages cautious optimism. On our last day in Lo-Manthang, we visited the Great Compassion Monastic School, which allows local students to pursue their religious studies without having to leave their homeland. Its enthusiastic abbot proudly showed us a classroom of boys with shaved heads who were memorizing and reciting Buddhist scriptures, in addition to studying secular subjects such as math and social sciences. These students represent an un-broken link to Mustang's past and a bridge to its future, upon whose shoulders the area's future likely depends.

Tim Farr is a former public servant who recently spent five weeks in Nepal and Thailand celebrating his retirement. It was his second visit to Nepal, but he and his wife Melanie hope to return.