Start walking and get in the best shape you can. Read up on "one bag" travel and ultralight hiking (don't over pack). Learn about layering clothing as that will be the bulk of your load. Search on weather history data for region/time you will be traveling so you know what to expect.. Learn as much Spanish as you can and read up on local history culture so you can appreciate what you see.
You will be getting a microscopic view of the region. It is so much different than motorized travel.