What sort of life is this, I ask myself? Here I am sitting on a rock, with my feet amongst yak turds, watching a line of those same huge beasts plod slowly home in the twilight towards a collection of black tents - nomad's tents - on the opposite hillside. Beside me a turquoise stream froths over frozen rock. I washed my hair in it soon after we arrived at tonight's campsite and I swear it was the coldest thing I have ever done. Right now Mother Nature is blow-drying it for me - which is a pretty chilling experience too.

We have set up our tents down here in a such a deep valley that at six pm the sun has almost set behind the fir-covered hills, they are so very high and steep. This place is awesomely beautiful. In fact the whole area of eastern Tibet (or western China depending on your particular political viewpoint) is frankly jaw-droppingly splendid.

You round a corner and what could be The Rockies, snowy, majestic, their lower slopes draped with firs, is framed by rocks so stark and purple (yes, purple ) that you wonder if you've wandered onto a film set. Just kilometres later you enter a gorge where a Grade Six whitewater river charges around boulders the size of semi-trailers. You look up to see where they might have come from, and shudder.

The cliffs are skyscrapers, massive towers of orange rock.

Then, a blind corner, a detour around yet another landslide, and without warning you have plateaued-out and find the road winding across a grassy yak-dotted plain. Clusters of adobe houses reflect the soil-type. Sometimes orange, sometimes mauve, sometimes taupe. Sometimes whitewashed, and with brilliant intricate patterns around the windows, lintels and under the eaves.

Other days we snake ever upwards, switchbacking towards the clouds, breathing the thin air greedily, and snatching stomach-churning glimpses of the dropoffs from the road. No use in worrying about what would happen if your driver makes a wrong decision here, or meets one of those overloaded buses without warning. Better to concentrate on the things that are real. The copper-coloured grass, uplands covered with rhododendrons, fluttering prayer-flags - red, blue, yellow, green and white - at the highest passes. And the people.

They seem as interested in us as we are in them. I get the feeling they would do anything for a camera to have some souvenir of these strange pale round-eyed aliens that pass noisily through their lives. They pose artlessly - yet so artistically - for us. Three children, arms linked, in front of a snow-caped mountain. A woman and her mules silhouetted against the sky which, if you called it blue, would be a pale description. A snow-goggled character who ambles out of the white-out the day after the blizzard blew our tents down and stands goggling at us, as we frame him with our high-tech cameras.

In some areas, the people wear black flat-brimmed hats, and many times we feel tricked somehow, imagining we have slipped a continent and hemisphere suddenly, slipping effortlessly to South America. Even the high cheekbones and darker skins carry on the deception. You rack your brain for some ethnological reason. Perhaps an ancient migration through the Bering Straits and a long trek south? Who knows? Their history swirls with mysteries.

The women's long dark hair displays their wealth - huge hunks of turquoise, real and brilliant, sewn or plaited into it. And from their belts hang silver daggers, encrusted with coral and more turquoise. One morning we woke to find a circle of observers. 'Our fan club' we called them, but really they were already on the job. Long before breakfast I had bought a ring and a knife and a hand-made needle-holder from one young woman - warmly dressed, as you have to be here - and she quickly shoved the wad of yuan that I paid her, deep into the folds of her thick dirty grey cloak.

This often bitter climate – milder now in late September when we visit – scrubs the children's and women's cheeks raw, rouging them scarlet, aging them. Yet there is a childlike simplicity, an innocence, too. One man, his head swathed in a skein of red, a striking sign that he belonged to the local Khampa tribe, muttered and smiled as he tried to understand our questions. We passed the phrasebook between us and he politely tried to make sense of it.

What can you say about these people who live under Chinese rule, but who are no more Chinese than we are Indonesian? These people who love to worship, and seek peace to do it. Buddhists in a Communist country. Adherents of a more ancient belief system than the one that presently seeks to control them; gentle followers of a philosophy that forbids killing, who themselves have been slaughtered for their faith. Yet somehow there are always smiles. Always laughter and hands raised in salute and welcome. For it seems neither the fierce elements nor the bleak environment – nor even current events – can break the spirits of these feisty Tibetans.

Certainly butter lamps glow again now in monasteries throughout the country. Incense rises and the muttering sing-song om-chants continue, scarcely missing a beat. Maroon and saffron-robed monks pace the corridors while tiny novices hunch over their lessons, eager to do well lest they be reincarnated as a hungry hound wandering aimlessly in the dusty temple grounds.

On country roads we see pilgrims travelling the most gruelling way – prostrating themselves, then rising, moving up to the hand-print, prostrating again, then rising up still yet-again. A million stony body-lengths to Lhasa. Or more. In the capital itself there are dozens, hundreds, in slip-sliding prostration at the doorway of the major temple.

The head guide speaks excellent English, learned in Sikkim he tells me. He has a sweet Buddha-type face. The fellow that has shared the back seat of the four-wheel drive with us for two days now, speaks no English expect for 'one-two-three-four-five' which we taught him. I call him the Kitchen God, because he is actually the kitchen helper and he has a benign expression, even when dozing, as he somehow manages to do quite frequently while we judder across what passes for a road. I guess he is not so thrilled by the scenery. But then he came this way just last week with the convoy of 4WDs to Deqen to meet our group.

Our route has taken us through western China from K'unming, then a thousand kilometres to the border where we leave our Chinese guides and the rattly bus the fourteen of us have grown used to, and join our Tibetan drivers for the trek upwards. We are told that we are the first Australians to enter Tibet on this route and, foolishly, I long for a T-shirt, a bumper-sticker – anything – to proclaim this to the world.

We know that we'll reach passes of over 5000 metres on the route ahead and already our lungs are straining to compensate for the rarified atmosphere. Tashi Lachman, our tour leader, bosses us unmercifully: 'Don't rush so much. Do you have a headache? Take care. Go slowly!' But then she knows better than we do of course, that altitude sickness is debilitating and frightening at best, and can, at worst, be a killer. The usual antidote (descending immediately to a much lower altitude) is not available here, for Tibet is a massive plateau that averages 4000 metres in height. We must be especially vigilant. Even so, some need to use oxygen from the cylinder Tashi made sure was waiting for us in Deqen. Others complain of nausea, dizziness and, in my case anyway, persistent annoying insomnia.

What sort of life is this, I muse again, on my rock on the bank. What sort indeed as the spicy smells from the dinner tent tell me food is coming. Across the stream turf-smoke blue as the daytime sky, rises from the nomad tents. I wonder what they are eating. I wonder how they see this land, these wanderers who can pack their belongings into saddlebags in a yak-blink when the weather changes or the pasture for their stock disappears. I wonder if they even understand – or care – what a border is.

FACTFILE

Getting there: Independent travellers are not allowed into Tibet from China. Groups have to obtain permission for the towns through which they will pass as well as the monasteries they plan to visit. Thor Travel offers regular tours into Tibet, and employs local guides and drivers.

What to eat: Thor Travel takes much of their own food from Australia, although they will supervise local cooks in preparing meals for the tour members. These meals may include yak meat or Tibetan breads. Drink only bottled water.

What to take: Although the winters are very cold, spring and autumn can be relatively mild. Take a range of clothing that includes thermal wear and good walking boots.

Health: Altitude sickness can be a real problem. For the first few days at high altitude, avoid alcohol and excessive exercise, and drink plenty of water.