I drove from Long Island, NY to Cancun in January of '91 in a pickup with a camper on the back. Ive always wanted to do it again on a bike but I've heard nothing but horror stories about both the 200 mile zone south of the border and 300 miles around the crook / chiapas areas. Lawlessness.
I'd contact
Sanborn's for the latest info. Also I'd plan on driving a visually unappealing yet capable and fast bike and taking only what you're willing to lose.
You're trip and experience would be a super interesting blog / vlog