I haven't stayed here, but I took a look in their rooms last summer when we had lunch next door and I thought the rooms were very clean (not at all fancy) and the price was extremely reasonable, given the beautiful view. Skyline Motel, Epoufette:

http://www.upskylinemotel.com/rooms.html

It might not be an issue for you, but if anyone else comes to this thread in the future, I wanted to note that they take dogs at this motel too.

There are several motels in Manistique, some of them are right across the road from the public boardwalk and beach.

Most of them look nice and well-kept from the outside but I have never stayed there.

There are chain motels as well as mom and pop establishments. The Econolodge looks like it has a great spot right across from the beach, but again I have not stayed there.

You didn't indicate any details in your post, but West Branch and Escanaba are about 5 hours apart (per Mapquest). Is there a particular reason for a motel between St. Ignace and Escanaba as opposed to just staying in Escanaba?

We just drove that route a few weeks ago and believe me, there are plenty of motels. It should not be a problem finding one.