It is a bit futile to try to get away from the supposedly"deadly border zone " in hopes of getting to an alegedly paradisiacal village of peace and harmony.
Just about any town you may be able to ride to in a day from the border, or deep,deep into Mexico , will at some point in the past have had some sort of incident that was newsworthy, whether it was related to the narco wars or just ordinary criminality,or aboriginal disputes.
The important thing is to keep informed as to the events of very recent days involving the area you are aiming at.Watch the Mexican TV news when in your hotel, stay current and act rationally.
It is not very meaningful to know that three months or three days ago headless bodies might have been found at town X. When you get there the situation will have settled and returned to near normal.
So what if there are armed army patrols around town, that should only add to a sense of security .
Don , if you want to get out of the border zone ,that is fine but don't force yourself into an ironbutt day.Not worth it.I know of some gringo tourists who wound up riding tehir entire trip scared and in ironbutt mode trying to find the "safe" spots.
From Matamoros If you get to San Fernando, or Soto La Marina or Aldama or Cd Victoria at the farthest you will have done plenty riding for a day.Running for Tampico will just put you in that city by nightfall unless you ride way beyond the legal speed and not look at any of the scenery.
Remember Mexico roads ar marked off in km and you need to add in for the scenic slowdowns and esssential stops so 300km to 400km in a day is quite a bit.Doesn't sound like much but... .Really, it is