Wild Wild West: Uyuni, Tupiza and the Southern Valleys, 14 Days

The tour that keeps descending. It starts on the same Andean route as the Highlanders, crosses the salt flats, then turns south into Butch Cassidy country around Tupiza before dropping steadily through Tarija's wine valleys to the hot Chaco plains at 400 metres. Departures run on request rather than a fixed calendar. A sixteen-day custom version with two rest days runs in April 2027 and takes new participants; ask if that suits you better.

Fourteen days and 2,300 km from Samaipata to the Salar de Uyuni, then south through Tupiza's red canyons to the vineyards of Tarija and down to the Chaco lowlands. Thirty per cent dirt, topping out at 4,400 metres.