5 weeks in Central or South America

I'm heading to Central or South America for five weeks from Feb. 10th - March 15th, but I can't decide where to go. My top two choices are to backpack from Costa Rica to Guatemala or just fly into and out of Rio de Janeiro, see some of Brazil and be back in Rio in time for Carnival. I'd prefer to do the latter option, but don't know what it will cost me to spend 5 weeks living in Brazil on a traveler's budget. Anyone have any ideas what costs I should expect? During Carnival? All I need is a roof over my head, food on my plate, and a beer in my hand. I'd love to do a week or two of volunteer work too, so if you know if volunteer opportunities will be easy or difficult to find (with no knowledge of Portuguese or Spanish), let me know.

Dear Jordan,

I stayed in Brazil during 2002 summer (winter in Brazil) in a travel in Brazil-Paraguay-Argentina-Bolivia. Brazil is cheap, but not less than the other countries we stayed in the same trip.

Rio, comparing to another places in Brazil, is quite expensive, and specially during Carnival.

About Guatemala and Costa Rica, I have to say that we stayed in a trip to Mexico-Guatemala-El Salvador-Honduras-Nicaragua in 2000. Guatemala is a very cheap country, Costa Rica is not so cheap as far as I know (I have not been there).

Regards,

Aitor http://w3.to/travellers