We have a keystone cougar with an artic package that seems to do well. It has an artic package which basically means heated tanks and a skin under the bottom. It heats well, but will use propane. I have a generator that I use and an electric heater to help offset the propane cost. Have been in it many nights where it's been below freezing and haven't been cold. Not much help on the tent ends, but would think you would be fine down to about 30, otherwise it would be like heating a blue tarp fish house.
Big wheel house holds heat rather well, but pull like a tank, you give up the bigger tanks and room.