Camping in sub freezing weather

Those are pretty demanding temps even for a sticks and bricks house. I am not sure I would risk un-winterizing my plumbing at all if temps would be consistently below 0. Sure you have heated tanks but how much LP? Trying to run your heat in those temps for extended periods of time will burn through a lot of LP. Not sure what FW you have but even with ducted air to the plumbing and tanks, there is still a lot of risk in a length of plumbing or a pump or trap to freeze. If I am staying in below freezing temps, I will winterize, take bottled water and use CG facilities for showers. I wouldn't risk it, but that's me. Most production RV's aren't built to withstand sub zero temps for very long. At or below freezing maybe, but you are talking 20-30 degrees below freezing.