You are brave! I'd leave him home with family. Take him when he's like 8. He'll get a kick out of it then and will actually remember it when he's an adult.
This is what I would do, but MMM knows I am the last person to be breezy when it comes to baby travel. Backpacking through Guatemala with a non-mobile non-verbal kid sounds like torture to me.
If I enjoyed backpacking I would do it. Of course it won't be as easy as without kids but I think as long as you stay in safe, clean places you will be fine.