All of the state parks mentioned are good ones. Reservations may be needed for the most popular, or the ones with fewer sites that will accommodate your RV. We camped for many years in Wisconsin and love their state parks. True, hookups are electric only, and many sites have no hookups at all, but living there we got used to it, since that's all there was.
๐ I would add Point Beach to the above-mentioned parks; it was one of our favorites. The same caveats apply for this park as for the others.
Wyalusing is our favorite, and Wisconsin Ridge CG is the one in that park you want to aim for. Your best bet, if you can dry-camp, is one of the sites right along the ridge; they have no hookups, but most are large enough you'll fit, and the view right from your site is nothing short of spectacular - and unique!
Areas of Wisconsin to visit: Door County (Wisconsin's "thumb" - you can look WEST to Michigan from some of it); Wisconsin Dells (Mirror Lake is a nice SP for that area) - VERY touristy but the boat & "Duck" rides are worth it; the southwest "Driftless" area, which the last glaciers skipped; Lake Michigan (Kohler-Andrae SP and Point Beach SF are great for that); and along the Mississippi. We were never able to get "up north" so can't recommend anything from personal experience. While in Wisconsin, if you have the time, you can also explore the northeast corner and the U(pper) P(eninsula) of Michigan - and some nice SPs up there as well.
House on the Rock is totally unique and a do-not-miss. If you're into architecture, Frank Lloyd Wright's Taliesin is worth seeing. The International Crane Foundation is a wonderful way to learn about those amazing birds. All of these can be day trips from a base camp at Devils Lake or in the Dells area. If you enjoy history, camp at Kettle Moraine South and visit Old World Wisconsin - a delightful day seeing how Wisconsin's early settlers lived (original homes, barns, etc. from around the state were moved there & reassembled, with living-history volunteers giving presentations in them.) Lake Geneva is very nice but we were not impressed with its SP (Bigfoot?) and prefer to camp at Richard Bong SRA (nice campsites - if you're going to go there, PM me for campsite # recommendations; that was our "local" CG for many years.)
2020 Toyota Tundra CrewMax 5.7L V8 w/ tow pkg, Equal-i-zer
2020 Lance 2375