Originally Posted by christep
...you might need to buy two extra segments in addition to the 4 allowed to fit it in (which is OK so long as you stay under 20 air segments in total)...
... or use LAN's South America AirPass which, for the the places the OP wants to visit (Patagonia, Lima, Buenos Aires, but not IPC), can be cheaper and does not take away any of the 20 segments.