thought I gonna share my experience with everyone.
I flew into Belo Horizonte with no local currency on me.
The bank was still closed ( at 9am) and once it opened
I learnt they don't change small amounts or don't accept customers without account, something like that.
Anyway, it took me a while until I learnt HOW TO EXCHANGE MONEY, just buy some small items at the airport's convenience store, offer them US$ and they will give you the change in local currency.
I assume many Latin American airports offer this "service", or they just got the meaning of "convenience store" wrong
As to flight options, from here I would check direct flights to Washington DC or Chicago,
flying over the North Pole is kind of "short distance". Then on to South America.
( Though I have never done this, I have looked into it )
Keep in mind that flying to/through US is very rigid these days.
Also,if your final destination is not an airport hub then try to figure out whether there is a direct connection from Madrid or Lisbon.