Take your time and take plenty of pictures, so you can enjoy it both now and later. I'd suggest working your way along the lower peninsula's Lake Michigan shoreline. Silver Lake SP, Ludington, Sleeping Bear Dunes, Traverse City, Charlevoix, and Mackinaw City are all interesting. In the upper peninsula, some of the highlights include Tahquamenon Falls, the big spring at Palms Book SP, the Pictured Rocks (you know about of course), McLain SP and the western Keweenaw Peninsula shoreline all the way to Ft. Wilkins SP, the Porcupine Mountains SP (both east and west units), and Bond Falls near Paulding.
The shoreline and state parks N of Duluth are great, too. Be sure to stop at the Palisade Head (south of Gooseberry Falls if memory serves). And in Grand Marais, don't miss Artist's Point out past the coast guard station... either before or after you have pizza at Sven and Ole's.