- The peaks in Patagonia, most of the time requires some very good skills, and the weather can be really nasty. However a great advantage is that there is no acclimatization required as the highest (Fitz Roy) is 3400m high
- The good things about Bolivia is that you can acclimatize easily as La Paz is already at 3600m. You can take the opportunity of visiting Lago Titicaca (3800-4000m) and Salar de Uyuni/South Lipez (3600-4800m) to improve your acclimatization before starting climbing.
Other advantage of Bolivia is that you can start by climbing snow-capped volcanoes such as Parinacota (6330m) or Sajama (6500m) as a traininng and then carry on with more technical peaks such as Illampu and Illimani (both above 6400m).
I know a good agency in La Paz if you need : "Alberth" on calle Illampu.
- I haven't been to Cordillera Blanca and Huayhuash, so I cannot say anything... but it is supposed to be spectacular. A guide is now compulsory for the Blanca one I think.
- Another spectacular area for easy climbing (with no snow though) and great to acclimatize before going on more technical peaks is the Puna de Atacama. And then you can go for Aconcagua with such a training !