The entire island is about 6 miles round trip. If you cross through the center north to south and cross over the bridge you can turn it into a 20 mile ride. The views are great and you can always have a picnic after your ride.
This is the middle of other rides I have mentioned. However, you can park here and get on the bike path. This is nice if you are riding with younger children. The path goes north and south. There is also a spur that goes west along Recor Rd. You can use this path to do a circular route to St. Clair and back along the water. The loop is finished except for about a mile in St. Clair.
This is a good starting point for a ride from to New Baltimore to as far north as you want. A Bay to Bridge (Anchor Bay to the Blue Water Bridge in Port Huron) It will be about a 50 route when it si done. As of 9/2005 only parts are complete but the road along the water has a good shoulder for 95% of the ride. I ride this a lot on Sunday mornings and there isn't a lot of traffic. You can park at the city park. Travel north on Main Street until you intersect with M-29. Follow that north. (There is a public beach at the park so bring your bathing suit and you can swim when your done.
This is about a 30 mile ride. About half is on a road with a good shoulder to ride on and the other half is paved bike path. I park in the parking lot by shopping mall and then ride south via the mail road. You will pick up a bike path in about a mile. You can follow the path to Marine Cityand then follow the road to the State Park. You can pick up the path again at the park and or continue along the water.