If there is anything I can do to help you have a best experience ride PM me.
If time is an issue I recommend you boogie down from Northern Mexico to the norther side of Mexico City, at Tula, take the outer circuit toll highway into Puebla, you will pass Teotihuacan Archaeological site area which is nice if you have never been there, cheap and decent hotels are adundant in the area. From Puebla you can go through Tlaxcala to Xalapa down to Veracruz and on over to Catemaco, Villa Hermosa, Palenque, etc. avoiding the toll roads most of the time and into warmer weather.
Remember that the TOLL roads are now at 50% of auto tolls for motorcyclists. So the boogie down part is cheaper.
Here are some good links for you
http://archaeology.asu.edu/teo/
http://www.maps-of-mexico.com/mexico_states.shtml
Have fun and be safe
El Stigo