sarah.simon wrote:...Then again, a resident of El Paso or Tucson or San Diego might chime in to say they cross the border in their own vehicle with no special precautions and have no concerns and that I'm just a Colorado worry-wort.
A select few areas south of the border allow one to drive their vehicle in from the USA in so-called "hassle-free" zones. Normally, driving any distance into Mexico would require you to register the vehicle with Mexican authorities, a big paper-work hassle. These hassle-free zones usually involve high numbers of American tourists to popular Mexican locales. Whether you get hassled by other means is an open question. Mexican insurance is still a requirement.
I think having a reasonable amount of concern is good. Many of the more remote areas near the border are essentially lawless in the literal sense of the word. It's a shame since there are some fine peaks plainly visible just over the line, but seemingly a world away sometimes.
Some of the border areas are safer than others, and frankly, you might experience more of a hassle on the American side depending on where you are. Juarez is a mess and I personally would avoid it. The border towns along the Arizona line vary: Agua Prieta is nice, Nogales is okay, Sasabe is scary, Sonoyta seems okay, San Luis is a mess. Some towns are literally on the border and you may as well walk over and catch a bus. Others lie a few miles inside Mexico, in which case it may be okay to drive in and park in the town if you feel it is safe to do so.
My wife and I encountered some (human) coyotes on a hike in the Huachucas in Arizona, and later some Border Patrol on patrol guys who affirmed that we are quite safe despite our encounter. The smugglers, as wretched as they are, generally leave civilians alone. Bad for business. I have bush-camped in California within a half-mile of the border with no issues. On the other hand, I have a very real worry about exploring the Cabeza Prieta in Arizona due to its ongoing smuggling problems - I don't feel safe being within 10 miles of the border, much less a mile. Again, some places you'll be 99.9% fine, other places have cause for concern.
If you want a peak in northern Mexico, want to drive over and feel generally very safe, and visit a truly amazing, unique environment, go check out Cerro Pinacate in northern Sonora:
http://www.summitpost.org/mountain/rock ... acate.html