I just know Bolivia, not Brazil. Think your bus route would be La Paz, Cochabamba, Santa Cruz, crossing the border at Puerto Suarez and then heading north to Caceres. Highway from La Paz to Santa Cruz is paved. Gravel/dirt road from Santa Cruz to Puerto Suarez is being paved, but have no idea when it will be finished. Took that road from San Jose to Santa Cruz in 2006; one of the worst roads I have been on in LA. Took us over 8 hours with an excellent driver. Suggest flying from either La Paz or Santa Cruz to Puerto Suarez if the paving has not been completed. Or can take the train from Santa Cruz to Puerto Suarez; runs daily. For a Bolivian travel agent in Santa Cruz who can give you info on bus lines, a reliable agency is rosario tours. info@rosariotours.com. Need a yellow fever vaccination and visa is $100/person.