Hi Paul,
To give you a rough estimate:
*
Accommodation: Around $30 per night
*
Food: Around $15 per day to eat
*
Activities: $15
*
Transportation: $50 for bus tickets, getting around, etc
So you are looking at around $4000 spending money for a couple of months. However, in some places you should be able to save some money, may be cutting down on fun activities, and so on.
I would advise to carry on you as much as you are comfortable with. You will need cash on you as you cannot relay simply on credit cards, traveler's cheques, etc; and you will save a small fortune in the process. The reason I say this, it is that you might be limited on the amount of money you can spend on a credit card.
Traveler's cheques can be a hassle because there is only a couple of banks (Banco de Brasil, etc) in
Brazil where you can exchange them commission free.
Hope this helps
VacationBuddy