This application build on the top of my another free app, My POI KML Viewer, which means that you will be able to open your own KML and KMZ files and navigate to selected waypoint, both online and offline (if selected navigator allows offline navigation).
In addition to this, MI Parks allows you to purchase different collections of the State of Michigan parks, campgrounds and trails coordinates and description. Once you have downloaded collection it will stay on your phone, so you would not be depend on the network access.
Collections can be purchased individually or altogether, which will be significantly cheaper. Also you will be able to download small samples of the collections for free.
Currently it have following POI collections available for purchase for $0.99 - $1.99:

Free Sample Michigan State Forest Campgrounds
Michigan State Forest Campgrounds
Michigan State Parks
Michigan State Campgrounds
Michigan State Trails
All Michigan outdoor