Hey mate,
I just rode up through Mexico, over 2 weeks though, as I was running out of time to catch a plane in the states. I headed from Guatemala at the El Ceibo crossing. I skipped Chitchen Itza, Cancun etc and headed up the guts of Mexico, skipping Mexico city and Guadalajara. I visited some old colonial cities and then hitup Copper Canyon as well.
The entire time in Mexico though I never paid for accommodation. I was lucky to meet a fellow biker in San Miguel de Allende and crashed at his place for 2 nights but the rest I entirely camped, from North to South. I didn't camp close to the border to USA though.
You will find people will be very warning to you, asking "tienes pistola" (gotta gun?), and will warn you off wild camping. I find a BEAUTIFUL place to camp on the river in Rodeo, Mexico but was told it was dangerous to camp. I never had a problem camping, but mostly camped in cattle paddocks (after asking), restaurants I'd eaten at and recreational sites (mostly in the south).
I also broke down with a melted wiring loom in northern Mexico, beside the road for 5 hours. A rolled back down the road to a guy who'd just broken down as well, he offered me a

, fuses, duct tape and pretty much offered me a gun. For five hours I worked away until when I thought it was repaired the main fuse blew again. So I stuck out my thumb and the 2nd vehicle that passed me (first was a van, so no good) was a pickup and 3 fellas gave me a lift 15km back to town where a local mechanic let me camp out behind his workshop and work into the night on my bike.
Mexico, can be dangerous. Be sensible, heed the warnings, read the news and government updates on the country. Although, like most places is hyped up by media and people who haven't been there. It was a beautiful country with beautiful people, and I had no bad experiences there (or I could've just been lucky). Camp mate, have fun, but stay sensible and trust your gut. Contact me for any direct questions you may have!!
Good luck!
Rossy.
Rubber side down amigo!