Yes black4vcobra, from my understanding and research, there are highway legal vehicle trails, and atv/snowmobile trails (obviously these are off-limit). I got a map from the ranger station in Lakewood that has the trails marked, so as long as you obey that there shouldn't be a problem. It's a pretty lengthy network of trails. And yes, it was a day trip for me on a Sunday. With more people I would definitely camp. There's a campground not 10 minutes from where I started on the trails.
Sidenote: The picture of the muddy ruts was not me intentionally being wild and reckless. I accidentally went down a muddy trail and didn't want to stop for fear of getting stuck. Still ended up getting stuck though.
I would be down to start a WI 4Runner/Offroad facebook group if people would join it.