We came back from Bolivia 1 month ago. We did a 4d3n tour from Tupiza, just showed up the day before and booked one with Tupiza Tours. The major tour agencies seem to be booking and filling up jeeps up to the night before, so you do not have to book ahead of time. It was a great trip, a very comfortable jeep with only 4 tourists in it (Uyuni based jeeps squeeze in 6), an experienced and safe driver, one cook for 2 jeeps providing 3 great meals a day (including lots of vegetables!). All jeeps from Tupiza (in our case about 8) stick more or less together, and together bring a car mechanic (needed..driving over rough terrain). Prices from Tupiza seem to be a bit higher than from Uyuni but are worth it (better quality, drivers,food, less crowded , 1 extra day ). We paid 1250 Bolivianos/person excluding another 250 Bv entry fees.
Other places we enjoyed; Tarija, Valle de los Condores, Sajama, Isla del Sol.
Transportation; many long distance busses only travel at night, however micros and trufis (shared taxis) travel more frequently at all times of the day for roughly the same price.
Thanks! I've pretty much decided to do the Tupiza tour instead of Uyuni. It ends in Uyuni doesn't it? Was hoping to check out the train cemetery too. If your Tupiza tour ended in Uyuni, was it difficult to get a ticket out of there? I've read that you need to buy the tickets leaving Uyuni ahead of time since everyone is usually trying to leave at once.
And, how did you get to Tupiza? I'm wondering if it would be better to break up the long trip by stopping in a couple cities/towns along the way, instead of a long night bus, etc.?