I just did this for Thanksgiving in a Coachmen Concord 275DS. Went to Great Basin National park. Baker,NV was the town i stayed in, was in the low teens at night. Now the Concord in no 4 season coach, but did just fine with some planing. Heavy blanket over the cab, and a heavy blanket over the big rear window. I did run a 1500 watt heater up front just to help but it was not really needed. ( dry camped on the way home almost just as cold, coach heater was just fine) I have heated tanks and they work, but the gray is on the passenger side and its drain is on the left. so the tank was good valve was frozen.