Currently as I type this I'm at a restaurant, but the RV is in a membership campground (Outdoor Adventures INC, Lakeshore Resort, Davison (Really Richfield Twp) Mi. THey do offer year around to members but you still have to follow the rules. RV can be left on site all winter (NOT PLUGGED IN) but you still do your 2-3 weeks in one out bit. Or every weekend, I'd winterize (Dry method) before leaving campground since you can't plug in.
NO water,, Sewer is ok but no water. Only selected bathouses open (You can get water there to fill your on-board tank)
ME... I'll be in Oconee, County South Carolina where freezing is not such an issue and the parks are open year round :)
How best to wnterize.. Strap snowblower to front of Rig, Drive south, when someone pushes their head back, Scratches where their hair used to be and says "What the ()@!#$ is that?" you are winterized.