Here is a RVerSkier thread from a few years ago:
https://forum.pugski.com/threads/17-camper-friendly-ski-resorts.131/
Aspen Ski Corp owns the Aspen-Basalt Campground and they have closed it down and are building staff accommodation on the site. There might be some overnight parking allowed in a parking lot across from the Intercept Lot or I might try driving to where the plowing ends on highway 82 past Aspen where Highway 82 closes for the winter.
Meadows Campground near Sun Valley is open in winter and was $35/night, electric only, no water, no washrooms.
Whistler RV Campground about 10 miles south of town, is open in winter and $40CDN/night for electricity with washrooms/showers. Steep switchback access from the highway.
The Government Campground near the Village of Lake Louise has some sites that are plowed in winter and 24 hour washrooms/showers for $35/night and less than 5 minute drive to the skiing. Go to the Alberta Rockies in March or April when the sometimes brutally cold mid winter is over. There is good Springtime snow preservation in the Rockies.
Most B.C. resort allows overnight RV parking, Red and Whitewater have $10/night electric plug-ins.
There is a campground open in winter near Jackson Hole but the recently remodeled Motel 6 in Jackson is $50/night in winter and is about the same price as the campground and there are other cheap lodgings in Jackson.
Sandy Utah also has cheap Motel6 and other cheap accommodation. I have also stayed in my RV at the Park and Ride and took the bus to Alta/Snowbird for around $5, similar cost to gain access to the swimming pool/sauna/spa at the Alta Canyon Rec Center across the street from the bus stop.
SnowBasin, Utah does not allow overnight parking but there are some snowmobile staging areas nearby.
I have stayed in the parking lot at Winter Park on the shuttle bus line with no one bothering me.
At Copper the security guys were on me as soon as I pulled onto their lot. "No staying overnight in the parking lot but the Walmart in Frisco about 6 miles away allows RV parking", they said. The sign in the Walmart parking lot says "No Overnight Parking" but I staying around the side of the building with no problems and there were never less than 6 RVs in the lot while I was there for 4 or 5 nights.
The official policy at the Home Depot in Avon, near Vail, is "No Overnight Parking", but no one says anything or checks and there were several RVs there when I was there a few years ago.
When Moonlight Basin was separate from Big Sky it was OK to stay in one of their rarely used parking lots. Now they are part of Big Sky, the security guys came by after my second night and said "No Overnight Camping Allowed, but you can stay one more night before you have to leave."
Also about a mile or so past the turn off for Big Sky is a snowmobile staging area but without 4X4 it could be tricky getting in and out.
Bridger Bowl: Check with Guest Services and they will tell you where to park.
My fallback last resort position is to find an auto repair shop or RV store to park at for the night or pull into a private business parking lot after they close and leave before they open in the morning.
Generally speaking I find it is better to apologize after the fact than to ask for parking permission in advance and then get turned down.
