Even on a rig with no heated ducts to tank areas its going to take 10-12 hours below freezing to do any damage. Do you have power where you are going? If you do you can run a ceramic heater plus furnace. For dry camping you will need to conserve power as that furnace is going to run lots. Keep a roof vent open to allow dampness inside to get out so you dont get a buildup of moisture. Any external valves/pipes that start to freeze at night will quickly thaw in the am if they even freeze at all. Even though we criticize the build quality of our rigs they actually do pretty well in the spring/fall weather if your prepared. Enjoy the trip