I'm surprised I haven't seen this location in the DB or in the thread, so any Michigan explorers might appreciate this.
On the coast of Alabaster, MI [named because of the Gypsum mine], the is a loading dock that stretches into Lake Huron.
The land is very accessible and surrounded by rural land, so you shouldn't be bothered. You can access it by car if you park in the nearby Alabaster church just north of the land, or you can walk/bike to it easily since its off a bike path.
My plan is to wait until winter to walk out to it and see if I can explore the inside.