We have done traveling at -10F and stationary at -20 F. While stationary we had one month of below zero temps, hitting 20 below at night. We used a 150 gallon propane tank and small electric heaters in the basement compartments. We also had two 1500 watt electric space heaters running continuously. While traveling we did hit -10 F one night. We stopped at a state park campground with 30 amp hookups. Ran the propane furnace and 1500 watt electric space heater all night. We have also stayed in Walmart parking lots between zero and 10 F. We set the propane furnace at 50 F and ran the generator until we went to bed and again when we got up.
We have insulated pads we put on the windows and in the vents. We did have water in the tanks when we did the stationary at -20 F, but when traveling below 20 F, we don't put water in the tanks, but we carry gallon jugs of water and anti freeze. There are two types of RV anti freeze, -50 F and -100 F. The -50 F anti freeze freezes at +12 F and the -100 F freezes at -60 F. The -50 won't damage plumbing, but will prevent the use of the dump valves.
2003 Winnebago Adventurer 38G F53/ V10 605 watts of Solar
1999 Winnebago Brave 35C Handicap Equipped
1999 Jeep Cherokee & 1991 Jeep Wrangler Renegade