I had originally planned on staying at the Birchwood, but now I'm considering changing that to camping. Pitching a tent in Bill's yard is nice, especially for the late-night talking around the campfire. However, Wilderness State Park for a couple of nights would be a great idea - I like the idea of waking up next to some early-morning photogenic sites.
As far as I know, Wilderness has one large campsite with showers and toilets, consisting of two sections, one on the beach and the other back in the woods. I stayed there many years ago. It's not all that close to Bill's place - the road to get there takes kind of a big circle, I believe. There are also a number of rustic cabins ($60/night, I think), many of them on the shoreline and another in the interior which may be a hike-in rather than drive-in. I've never stayed at one of those.
In recent years I have only been to the south edge of the park. Maybe someone with more current knowledge of the northern part, which includes the campsite, will have more to say, and correct any errors I've made here.