Don't try to close your slides if there is snow on the slide topper. (Personal experience
). Just watch out for freezing and potential for burst pipes. I put a wireless thermometer remote in the wet bay so I can monitor the temperature from inside. Some RV's have heated pads under the tanks, others divert some warm air from the furnace to keep things warm down below. If things get too cold, it's usually easy to put a small heater in the wet bay. Some people just use a light bulb. You may need a heated fresh water hose, but an alternative is to use the internal fresh water tank and top it off in the middle of the day when things have warmed up a little. We camped all last winter in New Mexico with overnight temperatures down to 7 degrees and had no problems.
Bruce Dickson 2013 Thor Challenger 37GT, 5 Star Tune, Safe-T-Plus Steering Control with Air Trim, Roadmaster front and rear Sway Bars, SuperSteer rear Track Bar, Crossfires, 2012 Honda CRV on Blue Ox Aventa LX tow bar. Full timers since Jan 2012.