Tahquamenon Falls (Upper & Lower), Bond Falls, Pictured Rocks National Lakeshore (boat cruise out of Munising), the Sioux Locks (at Sioux St. Marie) are all must see's.
I really like camping in the State Parks - Michigan's UP has some great ones. They have electric only hook-ups (usually 30/50A), with water & dump stations near the entrances. Prices are reasonable, but you have to have a park pass (purchase one at Wall-mart or at the parks). You can plan your whole trip and make state park campground reservations on Michigan DNR's website - www.michigan.gov/dnr
. Since it's all rural up there, most every town has a propane fill center. If you don't already have one, I might suggest picking up a copy of "DeLORME's Michigan Atlas & Gazetteer". It shows all the waterfalls, light houses, and other attractions, plus state parks & rec areas, private campgrounds, fishing hot spots, golf courses, high quality maps, and a whole bunch more. I've used it extensively during my travels through-out the state. If you're looking for a more "rustic" experience, I'm sure Rustic Eagle can give you some insight. He's been all over the state, and is always willing to offer assistance to JOF members.
I hope you have a great trip this summer, and come back often!