How far north do you want to go?

I agree some time in Marquette and Munising (Pictured Rocks) is a good idea. There's a Holiday Inn Express in Munising that is surprisingly nice, with a great view and location. In Marquette, the Landmark is cool but can run pretty expensive. Both the Fairfield and Hampton on the waterfront are good options. Pictured Rocks is well worth the time and one of the great family trips we've taken.

If you want to reach the end of American civilization, there are few better places than the Keweenaw Peninsula. The Keweenaw Mountain Lodge is your best bet up there, but book soon. My guess is the additional jaunt to Isle Royale may not be in the cards, as the seaplane trips are likely booked by now.

Overall, make sure to hit Pictured Rocks, Marquette, and hopefully Houghton and Copper Harbor. And work in a drive on Highway 2, along the Lake Michigan shoreline.

I am not as high on Tahquamenon Falls as most people, but maybe most people are right and I'm wrong.