One handy trick I have used for winter sailing that translates nicely to winter rv camping is to use a coleman white gas lantern for lighting in the evening. This will save your batteries, and the white gas lantern throws off a lot of heat which will also save on propane for your furnace. White gas does not produce a lot of water vapour so condensation is not an issue. Make sure your CO detector is working, although I have never had a problem with this. Also (obviously) make sure your water systems are winterized. I always put the plugs in the sinks in case anyone accidentally pours water down them.