Look here for March 2013 temperatures at Yellowknife:
http://climate.weather.gc.ca/climateData/dailydata_e.html?StationID=51058&timeframe=2&Year=2013&Month=3&cmdB1=GoIn March 2013 we drove from Whitehorse to Liard Hot Spring to enjoy some spring soaking. Had overnight temps to -20C. On other trips we've camped at -40 so weren't unprepared.
Used the generator for the truck's block heater for about an hour before starting it in the morning.
Propane furnace worked well. Fridge didn't need much, but it also worked. If you have freezing temps you may wish to have your propane tanks purged of moisture before heading out or the moisture can freeze in the regulator and stop all flow. At -40 the propane starts to liquefy and becomes very inefficient. It still works, just not well.
No water in the RV. Carry water in a jug or water cooler for drinking and washing. Decide for yourself whether you feel comfy with putting water into your grey tank. We always have and then wait for it to thaw to dump it. We try to use the outhouses most of the time though; take some Styrofoam insulation and cut yourself a toilet-type seat -- the styrofoam is much more pleasant to sit on than a cold plastic seat.
Put area carpets on your floor to help keep it warmer. Block your windows to preserve heat. Have loads of layers and blankets.
Ivory dish soap doesn't freeze as quickly as other dish soaps. Have hand sanitizer available for hand cleaning.
Take dogs to sleep with you at night ... three dogs apparently do the job well (Three Dog Night). :B
March 2013 trip
here.
December 2001 trip
here.
December 1998
here.