I haven't been through that North Eastern part of Mexico, and don't have recent information, but I think I would stay away from it and go further west to Nogales then go down the western side of Mexico to Chapala. I know that would add quite a bit of travel to your trip, but may be something to consider.
I would try searching google for recent safety information both from official sites and personal reviews for cities along the border states, and make a more informed decision.
Our family is from Chapala, and we used to travel that route from Nogales every year, but that was a long time ago, so I don't really know how it is now. I wish I could do a trip like that - sure am looking forward to retirement! Good luck and have a blast!