I recall my Mom and Dad talking about this area of the country - I think they went there when they were just a young couple. Also something about Calumet Island?
p.s. The photo above (by the ticket office) is one I tried to send to you and Bonnie in a conversation!
Did you hit "The Mystery Spot"? Never have stopped, myself. Then there's that "Visit Rock City!"...about a gazillion signs posted along I-75 north-bound. That many signs we had to stop...Frankenmuth...another good one, Christmas City. You can't find the ornament you're looking for there you're not trying hard enough. Not sure about Calumet Island. There is a Calumet just up the road...almost became the state capital...now they have to do a remodel every time they film another episode of Gunsmoke. Hemingway spent some time in that end of the U.P. after he came back from WWI Europe...and a more recent writer, Steve Hamilton, places some of his stories in that end of the U.P.