[us2indaup]

Everyone elses suggestions are excellent, and I'd like to sugest this trip itenerary for you.
Since you'll be coming in from the west, I'd recommend crossing at Ironwood rather than Menominee, taking the byway to the Porcupine Mountains (hwy 519 N, just outside of Wakefield), and go up to the Keeweenaw from there. (Be sure to see Lake of the Clouds overlook in the Porkies). There are some interesting historical things in the Keeweenaw, such as the Quincy Mine Steam Hoist and a tour through part of the old mine, as well as a few smaller mines offering tours, and a must-see up near Copper Harbor is the Brockway Mountain Scenic drive, which is breathtaking. From there your best bet would be to go to Marquette, stopping at the Yooper Tourist Trap in Ishpeming - can't miss that! From Marquette to Munising and the Pictured Rocks, which has awesome views over Lake Superior. You can take a boat tour from Munising along the cliffs, you can't see them as well from the land . After Munising you might be interested to see the Seney Wildlife Refuge, although your kids might find it boring. Theres really not much worth seeing east of there unless you go to the Soo to see the wrecked lifeboats from the Edmund Fitzgerald on the Valley Camp museum ship (I was awed by how twisted they were). St. Ignace / Mackinaw City / Mackinac Island are one big, overpriced tourist trap with shoulder to shoulder crowds and expensive hotels. If you're going to stay there, book a room well in advance - its hard to get a room even in the off season. Other than taking the ferry boat to the Island, though, theres really nothing to do there. From there you can go west back along US 2 through Manistique, stop off to see the Big Spring, which is just a couple miles off the highway and WELL worth seeing (you can see the lake trout 50 feet below, the water is so clear). Thats just about everything, except of course the waterfalls. Tacquemenon Falls is pretty, but there are dozens upon dozens of other falls all over the U.P., several right on the road up to the Porcupine Mountains.
Hey, have fun!!!