Meet at the Conservatory, then check out the Aquarium and Museum (admittance is free), do some walking around the park, gaze at the landscape. For more information on fees/hours of operation (10a-3pm on Sats), go to http://belleisleconservancy.org/visit-the-park/activities-attractions/. I suggest you bring a lunch. E-mail me via Meetup if interested in carpooling.
Belle Isle Park is now a State of Michigan park under a 30-year lease agreement signed by the City of Detroit. Under the agreement, the City maintains ownership of the park, while the Michigan Department of Natural Resources manages the island park. Belle Isle, a 982-acre island, officially became a state park on February 10, 2014. One of the first changes Detroit residents and others will see is an $11 annual fee, which allows entry into all state parks. The fee will be gradually phased in during the first year of state management of Belle Isle.
Individuals who walk, bike or jog to the island will not have to pay the entry fee.