Did you 'call' any of them? Ya their websites will state when they open for spring etc. but most stay open all year.
Almost all of the CG's are open but the water is not turned on. You will have electric and dump hookup. Most have bathrooms that are heated so they leave the water on in them. you can shower there. It's best just to pull in these CG's and they will let you stay. If you call they'll say they are not open.
Call Coachman's in Lake Geneva. Small but nice and Lake Geneva is just down from it. If you look it up on line it will look like a mobile home park. But there is a section in the middle that is for RV campers.
I stayed there every summer when I was traveling! :C
We must be willing to get rid of the life we've planned,
so as to have the life that is waiting for us.