To prepare and choose the route I need to gather as much information as possible. I get information by talking to people who have sailed the route of parts of the routes. Especially for the route along Brazil and Argentina I will get a lot information from Brazilian and Argentinian cruisers who I met during my journey. I try to find as much as possible information online.
The books and websites that I think are useful will I write down in a list below. The idea is that this list will grow during my trip
Cornell's Ocean Atlas
Pilot charts for all oceans of the world
World cruising routes
1000 sailing routes
online cruising guides