Uh, did you say Mexican road trip as in you're going to Mexico in a CJ? You may want to google the recent drug cartel war happenings. Specifically, look at what they're doing to young females who are away from help and use the word 'Zetas' in your search.
I used to live in Mexico, I'm currently back in Texas where i hear the first hand news and I was Army SpecOps for years. Point being, Mexico should be right up there with a backpacking trip across Iran. All my friends still with the State Dept say it's not getting any better anywhere in Mexico.
OK, having said that...I'm as adventurous as the next jeeper, so of your really going I hope you have a blast. I would only attempt it in a well built CJ. I used to wander around Mexican junk yards looking for CJ stuff. Really never found much. That means if you break down your screwed. If it were me traversing the crazy roads of Mexico in a jeep, I'd get a CJ with a Chevy 350 and a crappy old paint/bondo job. Easy to find parts for and you'll fit in fairly well.