Last year a buddy and I found a nice little spot on some public land with a perfect hill and miles from any houses according to google maps. Only about a fifty yard field but fine to mess around in and fairly close to home. We shot there for an afternoon, didn't see a soul. Came back two weeks later and found the DNR had posted a "no target shooting" sign in the interim, guess someone saw us and decides they didn't like it, and I guess the local DNR was sympathetic despite the fact that it was perfectly legal shooting.
I've had some frustrating experiences on public land here in Michigan... And being 25 myself i always get rolling eyes and condescending looks at the local clubs from the old hats...So I hear you brother.