Salar de Uyuni
We started in Tupiza (Beautiful! Looks like Moab, Utah) on a 4 day 4-wheeling tour and ended in Uyuni, but we were going north. You may be able to do the opposite, although the last two days were the best so perhaps 2 days is sufficient. Seeing the geysers, seeing the green lagoon, sitting in the hot springs and of course seeing the salt flats in the highlight and I believe that all came at the end (beginning for you?). Once you get in the area of the salt flats, there will be travel agents at every corner to sign up for a 4 x 4 tour, so don’t be afraid to price them out.