Hey DR Rambler: You should be able to get a tire for a Suziki DR65o in just about every big town...including Mazatlan or Puerto Vallarta...and there should be no good reason to ever go to Guadalajara (in my opinion). I would head south along the coast and stay in Sayulita. Going to all those colonial cities is good but if it were me...I would stay along the coast and cut up to Uruapan and see Paricutin (one of the wonders of the world) then stay at Patzcuaro. This is the best colonial city in my opinion with Guanajuato a close second. the others have their charm but if you are pressed for time...you can miss them. Mexico City is very intimidating for most but I love the place...but you can bypass it and head to Taxco via Toluca and never see Mexico City. Then head to the coast and but don't stay in Acapulco. Ride south to Nexpa and then to Zipolito or Puerto Angel. Oaxaca is my favorite big city in Mexico and shouldn't be missed. Then to San Cristobal and Palenque if you have time. That should keep you busy.