My main concern now is figuring out if the bounce rate has to do with speed.
Yes, very much! Will you wait for a page that takes too much time to load? No, you will hit the back button. So does everyone else.
people search for "arica to cusco" and end up on this page
Maybe, but how much time do they spend there? Your pages are too short. Think of Wikipedia where most of the places you have on your site can be found with much more compelling content and photos. See the internal linking and the usefulness of the content there. Try something taking it as an example.
I am interested in the point alchymyth made.
Very valid point. But can you compare the time your visitors spend on your site?
I also get a lot of international traffic. Could this be the problem.
Unfortunately, I have to tell you that Bounce Rate which is a very important metric of SEO needs a lot of time and space to explain and to understand, and I do not think this is the forum for that.