The best alarm clocks are the ski patrol guys doing avalanche control work at 7am while you are nice and cozy in the resort parking lot.
Heat and batteries are the two big issues. You will find places for your skis inside your camper or truck, or outside under the vehicle.
A lot of campers/trailers use the catalytic (buddy style) heaters and leave two windows cracked open which really saves your batteries. You have to leave one or two windows open anyway or the condensation from the gear drying and you breathing will collect on the ceiling and drip.
We just use the camper furnace for our heat, and two group 31 batteries is plenty of amps for one night. For the second night we run the generator for two hours to give the batteries a quick charge for the second night.
Another note: we went to Stevens Pass last month and it looks like Vail Resorts is going to convert their RV lot to car parking. Not sure if there will be RV parking up there anymore.