Being a Michigan resident, all I can say is there are a HUGE number of shops to choose from. Even in the less populated, let's say north of Grand Rapids there are shops that a full of personality. As others have said do that google shops. There are four just in Muskegon. I have been to Quilted Memories in Montague but it was a few years back. If you go as far south as Holland, Pressing Matters is a lovely shop. You will have plenty to view.
Thrums, I think the notation that the store is closed is indicating their store hours. In other words, at the time of the search they are closed, not that the store is no longer in business. Have a wonderful trip of quilt shop wandering. Do let us know your favorites after your trip.