A good place to start is the Wisconsin tourist info building. Not sure where they are all located in Wisconsin but I think they are at rest stops. We have a big one on the state line of Illinois/Wisconsin on I94. We go out there and get information every year.
I haven't gone there yet this year. As soon as I have time I'll go scope it out and see what is there and pick up things that I can add here.
I also have some places I know of that I mentioned before that I would add, just haven't had time to post them yet. Will do soon.
pk
