Resolve the "beef" ?????
If the temps are going to be below freezing for any length of time, you need heat below the floor. That means running the furnace (propane consumption) or converting the furnace to also operate on electricity. There is an "add on electrical system" for RV furnaces. While it's likely to mean that you'll also need to convert to 50 amp shore power capability, there is a 30 amp system that can provide somewhere around 6200 BTU at the furnace (most 1500 watt "stand alone electric floor heaters are around 5600 BTU) which, in turn, will be directed to the ductwork which includes the "sub floor area", which will protect your holding tanks during extremely cold weather.
https://www.rvcomfortsystems.com/