It would be a great trip. I just planned a similar trip in a 412 to Panama, so I can't vouch for the South America sectors, but I plan to overnight at the Mexican border (on the US side), and cross Mexico next day to Belize. I don't want to overnight in Mexico if I can help it. As much as I love Mexico, I'd rather reach Belize that day.
Several guys have offered good advice on this thread, do be very cautious and get a handler. No-one is going to shoot at you just because you're there.
If you have a say in it, fly the trip for goodness sake, what an adventure. But if you don't feel confident about it, take someone with you who is, or use the container.
Best of luck, think it through carefully, these opportunities do not come along often.
Tam