Yup. I use my trailer all year round, so rather than winterizing, I just leave the furnace at 55 and leave the water heater on. I usually leave the water heater on propane, and it rarely fires back up, since it holds heat really well. This allows me to run a space heater for primary heat (I'm only plugged into 15 amp at home), then the furnace only kicks on when it's really cold.
If I have the cover on, the space heater alone is enough to keep the trailer from freezing, and I have a nightlight I place in burner compartment of the water heater.