Some winterized RV's have a heater mounted in the underbelly to keep the tanks and lines from freezing. There may be a switch inside to turn that on if you have it. Otherwise since it is only one night I'd just drain the tanks and lines in Arizona before I left and use the facilities in what ever CG you stop at for that night.
I spent a winter near IF once (Arco) and it got down to 41 F below once and never got above freezing at night for 6 weeks. That was back in the 1970's tho and I've heard it is not quite that cold there lately.