A couple of other questions...

1) Regarding visa costs and reciprocity fees- Ive read that in Chile, for instance, if flying to IPC from LIM you are not subjected to the same entrance fee as if you flew into SCL. If you then chose to go IPC-SCL it would be treated as a domestic flight and you wouldn't have to pay. Does this hold true for Argentina/Brazil as well (meaning if you fly into a smaller/domestic airport instead of GIG, GRU, EZE, etc. are there ways around these fees?) I'm specifically interested in IGR or IGU if I plan a trip to Igaussu Falls.

2) How many days (at a minimum) would I need for Machu Picchu from Lima? It looks to me like a minimum of 4-5. Is that correct? I'm thinking:
Day 1: Lima-Cusco
Day 2: Cusco-AC
Day 3: Machu Picchu
Day 4: Machu Picchu- Cusco (is this possible in one day with train schedules, and is it possible to get all the way back to Lima in one day)

Thanks for the continued advice and tips. Im hoping to take this trip in March so I've begun looking at flight options and intra-SA flights don't seem too bad. I found RT flights from Lima-Cusco for $125 and flights from Lima-IPC for $400 RT both of those seem much cheaper than the LAN Airpass I was trying to construct.