With my camper mounted on a 4-wheel drive pickup, I prefer to camp where other folks ain't. In fact, I take great pains to make it so. There's this place that I like to go. It's barely a track heading off through the desert. I wind through the saguaros, bounce across a couple of washes, and end up by a sprawling Palo Verde. Anyway, I'm enjoying a quiet cup of coffee when I hear a hum, like a thousand bumble bees heading my way. I look to the north and see a herd of ATVs heading my way. They seem...