The Andes : There are a lot of hiking opportunities in the Andes. I did quite some hikes and only needed a guide to go to the
Lost City in Colombia (I hear you, that's not in the Andes). All the other hikes in Ecuador, Peru, Bolivia and Argentina I did on my own.
Volunteer work : There are a lot of social projects in South America. They love an extra hand. You can read more about volunteer work here.
Jobs : Getting a job teaching English is not too hard. The pay equals social standards so it's enough to get around.
Spanish/Portuguese: read here
Hope this gets you on your way. Feel free to post in the appropriate forum if you have more questions.
Best wishes,
Mark