Machka and Rowan, if you havent already, there are a number of crazyguy journals of trips in Chile, Argentina etc. Ive followed a few because of my interest in Latin America, and while its not possible for me to do a trip like that now (time, family stuff, cost) the one thing that I remember from the journals are how the landscapes can be really quite stunning in places. Im sure you will get some responses here, but do check out cgoab for some really good pertinent info on all in the ins and outs of the various areas that people have travelled in.