The Ticker today covered the hidden parkland in Garfield Township. See: Garfield's Secret Green
Intrigued, I visited the Garfield Township Parks & Rec web site and found they have a Google Map of their parks:
View Garfield Township Parks in a larger map
and they have a PDF you can download of all parkland "including Grand Traverse County Parks, City of Traverse City Parks, and Grand Traverse Regional Land Conservancy Parks."