You have a lot of good options of some really cool places.
In MN, any where on the north shore will be pretty cool, Tetegouche State Park, Temperence River, or any where on the Gunflint Trail out of Grand Marais.
Wisconsin, definitely Apostle Islands, I've gone there multiple times. You can camp in a state park on Madeline Island, or better yet rent sea kayaks and go between all the islands.
For the U.P., Porcupine Mountains, and Isle Royale, which I just got back from. It's an epic place, if your willing to do some backpacking...
Can't go wrong with any of those.