1) Reserve and stay at a private CG (GS/KOA) that has hot showers and heated bath rooms. The CG owner and others will be there to help you if you have any unforeseen issues.
2) Be sure your propane tanks are full, the switch-over regulator works and there are no leaks in the lines or fittings. Test the furnace and the water heater BEFORE you leave.
3) Bring along an electric blanket (or mattress heater) and a good comforter blanket for the bed.
4) Thermal bottoms and wool socks are highly recommended because the colder air is near the floor.
5) A small electric heater (ceramic or oil filled) for supplemental heat during the evenings while watching tv.
6) Fill your FW tank when you arrive on site and don't expect to use a city water hookup during freezing nights.
7) Expect condensation to form on the windows and cold spots on the walls.
8) Bring a good bottle of cream sherry to help warm-up your insides.