Despite the fact that hitchhiking is discouraged by most people it is quite doable in Brazil.
Check http://wiki.apnchanger.org/Brazil for APN information
Brazil maintains a strict mutual visa policy. That means citizens of the United States will have to pay over 100$ and give finger prints, whereas citizens from EU countries can go without a visa. Also citizens of Thailand, South Africa, Namibia, Malaysia and New Zealand can stay up to 90 days without a problem.