I would do Bruno's, Grand Island, Valley Spur. They are all quite different. Bruno's is beautiful single-track surrounded by lakes and rivers with great scenery, Grand Island is old carriage roads with incredible scenery and high cliffs above the lake (saw an Eagle take off from below while peaking over the edge of a cliff), and Valley Spur is mostly a maze of two tracks through a very hilly area.
Previous discussion: viewtopic.php?f=31&t=112372&p=782389&hilit=valley+spur#p782389
Not bike related but a cool place between Munising and Marquette. (donation based) http://www.lakenenland.com/
The trail is the thing, not the end of the trail. Travel too fast and you miss all you are traveling for.