How to get a free DNR campsite or boat slip for the summer Updated Mar 08, 2021; Posted Mar 08, 2021 The Michigan Department of Natural Resources is looking for volunteers to host its campgrounds and harbors this summer.Kayla Renie | MLive.com Facebook Share Campground and harbor hosts volunteer for 30 hours a week. In exchange, campground hosts can camp for free for up to a month at 122 state parks and state forest campgrounds. Harbor hosts receive a free harbor slip. There is also a similar program hosting the Hartwick Pines Memorial Building. All volunteers must be at least 18 years old, provide their own camping or boating equipment, be available at least five days a week, and pass a background check.