Ok so I will say Mark has some really good points, however I am a Midwest girl investing in the Midwest because it is familiar and drivable and we took family trips there when I was growing up. @Vera B. is there a personal reason you have your eye on northern Michigan (family there, visit often, etc.)?
I will say that northern Michigan has done pretty well with rentals post-Covid. I have friends investing up there in Harbor Springs, which was recently voted in a study as one of the top 25 places to buy a vacation home based on home sales and vacation rental performance data. Traverse City is also a very popular spot for vacation rentals. Golf, ski, woods, lake, and outdoor activities draw people to northern MI. Heading south, we looked at investing in Holland, it's a great area with the state park, Dutch village, and tulip festivals. 2 reasons we didn't invest there: the beach and downtown area are not near each other and we wanted to be closer to the Chicago area. We settled a little further south with our STRs in southwest Michigan. The rentals in SW MI have had high occupancy as people working and schooling remotely have taken more "flexcations" away from the cities. Happy to connect if you have any questions about SW MI or STRs in general!