Originally Posted by miikkak

1) You have to get Brazilian visa before arrival (unless crossing illegally the border) and you pay it to the consulate in US. Argentina for now has the same logic as Chile but it has to be prepaid. Argentinian rules can change with little notice, check it 1 month before departure and again 1 week before departure.

2) At least 3-4 days are recommended for Cuzco. If you depart early (wake-up at 4 am) you can do a day trip to MP (return at 11pm) from Cuzco. By the way, Titicaca lake in Puno is very beautiful, only 5-6 hours by bus from Cuzco. If travelling to Lake Titicaca, you can fly easily to Lima from Juliaca (45 minutes from the town of Puno).

3) LIM-CUZ 125 USD, which carrier (some fares do have residency restrictions)? If planning in advance, there are better options than the airpass.