There are seasonal parks in the northern states that cater to long term guests. Some of them are ownership parks, while others have seasonal leases. During the summer they have activities, just like the snowbird parks do in the winter.
I know of two offhand: Tomorrows Stars RV Resort, near Springfield, OH, and Roaring Brook Park, near Stafford, CT. We've stayed at others, but the names escape me right now. They are all over.
Since we are permanent residents of Florida, when we go north for the summer we call ourselves "sunbirds" - escapees from the hot summer sun.
2004 American Tradition; 2014 Buick LaCRosse
Homebase in the Ocala Nat'l Forest near Ocala, FL