I don't think you are over thinking it. I agree, don't leave him alone at the motel. No telling what could happen since too many people have keys to the room. And even if you ask for no cleaning products to be used, if you are not there you would never be certain. I think I would stop at smaller restaurants, maybe more of a chance to be allowed to bring him in with you. I would offer small pieces of fruit in the car, that would give him some water and some food. But, as was said, don't worry if he doesn't eat much in the car. Please don't let him on top of the cage while driving - just imagine what would happen if you had to stop fast, or heaven forbid, you were in an accident.