We've winter camped in Mass for the past 4 winters. Both parks we've used run a winter "program" where you can leave your rig plugged in on your site, and you have weekend/holiday access, so NOT full-time winter residents.
We did this for 2 years at Normandy Farms, a fantastic campground with indoor pool/hot tub available all winter. The stopped their program, but sounds like they will restart this coming fall. $800 for 5mos, which for us is a great deal. Gets the rig out of the driveway, and we go camping almost every weekend.
Our first winter, there was a bad storm and the campground lost power for 5 days. Our batteries discharged and froze, which also took out the converter. We were very surprised that Normandy didn't call anyone (there were about a dozen "winter program" campers, but that was the first year they ran the program).
Needless to say, when we arrived on a Friday evening, power was back on, but we were not aware of what happened until we discovered our electrical issues.
Since then, we obviously keep a closer eye on things during the winter, and monitor power outages closely.
So...it happened to me
And I learned from it