“I just always thought there was something not quite right about this world,” Clay Greathouse said, as his truck climbed out of an arroyo and onto a creosote-studded lot near the town of Tombstone. It was a Saturday morning in March, an ideal time to be ambling in Arizona’s high desert, though if the truck broke down here I would certainly not want to be without my water bottle. The last street sign I’d seen was for Last Chance Road. Outside ou…