Best place to go backpacking is Ecuador. A really small country, bus fares to get around is 1$=1hr. In Ecuador you can go find the amazon rainforest (eastern side of the country), the Indies and the mountain cloud forest (mid part), some crazy ass volcanoes (closest points to the sun from the Earth since Ecuador is right on the Equator), the amazing beaches on the west coast with surfer towns and finally the Galapagos islands just off the coast. After that you can go to Columbia or Peru