Mick, your description of the Wild West is very true! One of our favourite places was Big Bend National Park, located south of Marathon. We stayed at the Gage Hotel after driving across Texas, then went due south toward the Mexican border. In early times camping was safe but we were still questioned of our whereabouts by a Park Ranger when a body was found at a wild camp site in the next canyon. The Ranger said he thought it was a murder and I asked if I should load my pistol. He agreed I should though a loaded weapon is illegal in a National Park. The case was eventually solved. It was indeed murder.
Later we were advised not to camp along the River Road adjacent to the Mexican border. Drug trafficking was the reason. My business partner of many years decided to retire and ran for office as a Constable in Bandera County. He volunteered to work with the DEA on stake outs at motels, etc. I used to visit him from time to time, wild country indeed.
When driving across the west, water was the first thing to pack into your trunk, plenty of it. Not drinking water when hiking killed many a visitor, we learned of a Frenchman who died of dehydration in Big Bend with an untouched supply of water in his back pack. Keeping a reserve of fuel was always a good idea when going off road, but you could survive a breakdown with plenty of water.
I read yesterday that one of the reason the SP remains popular is the variety of terrain the system covered, from the hottest deserts to the highest snowbound mountains. It embodies the Spirit of the West.