We've used our Navion up at ski areas a couple of times and in cold and sub freezing temps in the lowlands. I also know lots of folks that stay in their RVs at ski areas. The following tips are if you're dry camping:
Supplemental insulation: You'll need it of the furnace will be running non stop. You will want to isolate the cab walls/windows/windshield from the house part of the RV. The easy way is to use a good blanket to seal it off. We have a fairly exotic insulated curtain affair we made from Warm Windows fabric that goes around the inside of the cab so the rotating cab seats are still available for use. You will want to cover single pane windows. The easy way is Reflectix bubble insulation. Once again we made insulated window covers that snap in place. Better insulation means less furnace use.
Tanks: Tank heaters can only be run if you have lots of power available..this means with power beyond your batteries. I toss some RV antifreeze in the black and gray tanks to start the trip off so the valves have antifreeze around them. I know lots of folks that do nothing and wait a day after they come down to thaw out.
Fresh water: Keep cabinets open at night so air circulates as close to the plumbing as possible. The plumbing is pretty robust but it's best to not tempt fate. Everyone I know has frozen up at some time.
Batteries: You want to enter the evening with them fully charged so charging during the day is imperative. Many (including me) have little Hondas we use for battery charging so we don't have to run the big generator endlessly. You will want to have good batteries too. When the group 24s that come with the RV **** out, convert over to GC2 flooded batteries at the minimum.
Solar: This will help your cause a bunch but trees and snow can get in the way.
Heat: You can use a portable catalytic heater during the day or plumb in a permanent one. This will save battery capacity as there's no fan involved.
Moisture: It's gonna be a thing. When you get back to civilization you will need to dehumidify the inside of the RV. I live in Western Washington and this is a regular deal after every trip in the winter.
If I think of more, I'll add it.