We talked about going to the BWCA last summer but my getting laid off put an end to that, my friend ended up going out to Yellowstone with his girlfriend and a few others. For whatever reason we haven't talked about going there this year.
If you want rugged adventure that is 'closer to home,' I think the Boundary Waters between Minnesota and Canada are not far from Green Bay? Great for hiking, portage, camping, fishing, etc.
Funny, when I read that I thought 'Traverse City isn't in the UP (Upper Penninsula), as Cappy would say its in the 'mudder mitten.' But you're correct QLG its in the northern section of the LP. :p I've been to Mackinac a few times and that is pretty cool (lots of awesome history stuff) but its real 'touristy.'
Traverse City in northern Michigan is amazing. Chicago is always great in the summer (but miserable in August), plus the food is amazing (da Bears). I think in the summer the Kalamazoo/Holland, Michigan area has a bunch of festivals worth checking out too.