As for the dock, it depends on how much of a tidal change there is. Usually, up north the tidal changes are more pronounced, at least along the coast. From the looks of things, though, the tidal changes on Lake Michigan are tiny--often less than 2 inches. The floating dock is probably the last expensive way to go, no pilings to drive. And, you can always take it with you when you leave. All the other stuff is honey-do things.

Have fun,

Gary