I rode through a good part of your planned route last year. You can check out my observations on my blog.
I just got back 3 weeks ago from wrapping up my trip through Latin America. I have a DR650 all set up for adventure riding, but I'm not sure if it's your style. I wasn't planning on selling her, but I could maybe be pursuaded. You can find out how she is equipped from the blog as well.
I really enjoyed Mexico and hope that you will too.