No such thing as good riding spots in southern WI. Well SE WI anyways. The Monroe trail in SW WI is okay for an easy ride. Actually it's pretty nice for easy riding.
http://www.tricountytrails.com/
The Rockford park is actually Rocky Glen. It's small but has an interesting obstacle course, kiddy track and a decent moto track. There are a hand full of trails to ride too.
http://www.rockyglenohv.com/
The next park south of there is Fox Valley. This park is about 70 miles south of Rockford in Ottawa. A fun park, larger then Rocky Glen and far more to offer. Again there is a kiddy area and an nice moto track but the woods are nice enough to host AMA Hare Scrambles.
http://www.foxvalleyoffroad.com/
90 miles south of Rockford is Cliffs Insane Terrain. This park is a mudder's dream in the spring or even after a good rain fall. They too have a kiddy area but not much for moto. This place was built for the woods rider in mind with plenty of hills, valleys and terrain ranging from clay and dirt to rocky. The park also has a creek that runs through it. Not a park in my all time top 3 but easily my favorite for close day trip parks. Plenty of video on youtube.
http://www.thecliffsinsaneterrain.com/
I'm not sure of any norther IN parks but the Badlands is about mid state and well worth the drive. The park has a nice camping area right outside the gates with a clean shower house and restrooms as well as a small convenience store. This park was designed around an old gravel strip mine and offers everything from lots of sand/pea gravel, clay, and dirt. If you like any of the 3 you should like this park and there is plenty of mud too. It's not so much a blend of these items as it is sections of each. You will find plenty of vids on youtube of this place too.
http://www.badlandsoffroad.com/
To answer the thread.......... I live in Racine county in SE WI.