The trick, it seems, is to know how to lean. Quad-bikes are short and not very wide, so when the going gets rough they'll tip you off unless you get the balance right. Being what they are — peppy engines with fat tyres — rough is where you want to take them, so a little instruction is useful.

Anneké van der Merwe is definitely the woman for that job. She's a feisty blonde with an infectious grin that transmutes your sheer terror into fun in seconds. And she's a farmer, a real one, not one of those buy-a-plot-and-gumboots types that drive an unscratched 4x4. So she has a feeling for terrain, a fondness for the bossies and knows how to take a panting machine where few would dare to go.

Anneké studied cattle, sheep and vineyards at Elsenberg Agricultural College while her future husband, Willem, was swotting up apples, grapes, pears and vegetables. They appear to have met in the vineyard class. Then they both went off farming on other people's farms, which is what happens if you don't inherit one. Anneké did table grapes, then farmed freshwater crayfish and picked up a tour-guide qualification along the way.

After they were married they moved to Barrydale where Willem bought a tree doctor business and hired a farmhouse just out of town.

"One day Willem said to me: 'This valley is so beautiful. We have to show the world. Let's do it with quad-bikes.' That's how Tradouw Quads was born.

"Actually it's a good job it was," Anneké added thoughtfully. "I'm allergic to crayfish and the white sap that comes out of vines when you cut them."

Together with Oom Handrie Kriel, the farmer whose house they were renting, they hand-built quad-bike tracks through the Renosterveld hills and over Tradouw's Hoogte to the west, then up through the fynbos to the top of Langeberg which looms over the eastern edge of the Tradouw Valley.

Challenging paths that, nonetheless, leave a soft footprint on the earth. One sunny morning we gathered on Anneké's front lawn for a lesson, then headed into the Karoo to cut our teeth among the botterbome and renosterbos.

After that, we nuevo-quad-warriors boarded a covered wagon, sat on hay bales and were driven to be spoiled rotten with a lunch of homemade olive bread, cheeses, olives and wine at the boutique cellar of Joubert-Tradauw.

If you love old machines, then you need to know that what towed us was a giant, green, 1953, two-cylinder John Deere tractor in immaculate condition. If you're the type who'd trade a tractor for a first-class Cabernet Sauvignon anytime, then winemaker Meyer Joubert's your man. He knows his stuff and he makes some of the finest wines in the country.

The next day we buzzed up through the vineyards onto the Langeberg and began quad-climbing where only feet and horses would normally go. Quad-bikes are to hikers what bitter aloe must be to honeysuckers: a serious intrusion into their pleasure zones. But to sit and hike at the same time is exhilarating.

"People say quads are dangerous," I challenged Anneké

There were steep, rocky parts where the quads refused to keep all their wheels on the ground, and there were bumpy bits that had us standing on the footplates to relieve our battered posteriors. Slowly the valley fell below and a cool mountain breeze brought promises of restios clumps and giant proteas. Eventually we topped out and below us was the coastal plain just east of Swellendam, edged with the blue of the Indian Ocean.

We hopped off the silenced quads and picked our way to the cliff edge. A jackal buzzard was wing-dancing around a nearby peak named Misty Point. Far below, water from a stream plunging over the cliff was being turned to spray and watering a stinkwood and yellowwood forest in a deep, remote valley that must be virtually unreachable.

We sat down to another fine meal prepared by Meyer Joubert's cellar, then Oom Handrie Kriel told us about the huge leopards that prowl the mountain top and had been known to take down a large ox.

That seemed to be a good time to pack up and head downwards into the safe arms of the valley.

"People say quads are dangerous," I challenged Anneké as we paused for a rest on the lip of a steep descent. "What's your take on that?"

"Yaah, sure," she shot back. "Horses are dangerous, aircraft are dangerous. You can die on a drop of water. If you know what you're doing these things are safe. Anyway, what's living worth if you don't sometimes take a few risks?"