In the U.P. I would suggest Porcupine Mountains State Park at the western end of the peninsula. Rather than use Union Bay campground at the north end I'd use the rustic campground at the south end of the park near the Presque Isle River. The hiking trails in this very large park are some of the best in the eastern U.S. You can do some back country hiking or there are shorter trails too.
Also in the U.P. is Ft. Wilkins State Park in Copper Harbor, at the very northern tip of the U.P. in Lake Superior. There are hiking trails in that area as well as some great scenery. You can also opt to take the boat up to Isle Royal National Park in the middle of Lake Superior from either Copper Harbor or Houghton, further down the Keweenaw Peninsula.
Another U.P. destination is Munising. There is a tourist park campground just west of the city on Lake Superior. There are also plenty of hiking areas where you can hike back into some waterfall areas. Just east of Munising about 30 +/- miles is Grand Marais which has a great little municipal campground on the east side of town called Woodland Park. Between Munising & Grand Marais is the Lake Superior Trail for hiking. You can hook up to the trail just west of Grand Marais.
In the Lower Peninsula just north of the small town of Atlanta is Clear Lake State Park. You can go right from the campground and hook up to the North Country Trail for hiking. There are a lot of elk in the area as well as bear if you're interested in wildlife.