Sucre

Sucre needs 2 days: the white historic center (a UNESCO World Heritage Site) on one, and Cretaceous Park (with real dinosaur footprints) on the other. May-October is the dry season with mild weather, gentler than La Paz due to its lower altitude. It's inexpensive, among Bolivia's cheapest cities. It's Bolivia's constitutional capital (though La Paz is the seat of government), and its historic center, painted entirely white by municipal law, is one of the best preserved from the colonial era in all of South America.