L.H.
Our family likes to vacation in Michigan each year--we rent a lakehouse. We find them at vacationrentals.com and haven't had a bad one--the owners have always been very accomodating and the houses clean and comfortable. Me like this method because we don't have to drop 100's of dollars in restaurants. We can cook/BBQ ourselves.
There's also a wonderful vacation place in South Haven called *Chalet on the Lake*. I used to go there as a child. There's a pool, parks, and you rent half of an a-frame, complete with kitchen and screened-in porch.
Good luck--have a great vacation!