First: Great way to retire! Sara and I have "retired" to Peru, SA, to work and run a Moto Adventure gig (to keep us afloat) here in Peru in order spend the rest of our time working with the handicapped in the Andes.
Second: TAKE THE AFRICA TWIN!!
You will have so many more options as to routes!
Third: The northern Brazil, Peruvian, Bolivian Amazons are quite wet December to March (landslides on the jungle side of the Andes in Peru and Bolivia). Can be done if on pavement, but you won't make many kms a day! Off pavement in these areas are out of the question 2-up during these times. Plan your routes accordingly!
Southern Argentina and Chile is very difficult (cold, windy) June to August, but the north of each is OK at that time. Put either country sideways against... say.. a map of the USA and you will get the idea how many kms from one end to the other (and therefore climes!) each is! :confused1:
Fourth: Any info you need on Peru, Bolivia, or eastern Brazil I can provide, I would be glad to help. Visit us in Huanuco in the central Peruvian Andes!
Fifth: Avoid the South American Panamericana at all costs (tho it is a little hard to do in Chile!)! Higher cost, crime, and police. Take the inland routes! Honest humble people, cheaper gas, better places to see!
Cheers! The hardest part is behind you (the decision to take off!)!
Toby