Are they open year round?

They are open for winter camping, but no amenities. No restrooms or showers, so if you are self contained, go for it.

https://www.michigan.org/article/trip-idea/wonderful-locations-winter-camping-michigan. You can look here for places to camp in michigan. Just copy it to clip board and paste in Bowser

I do not believe that the campground is open all year round.

This is a customer review site not the store try calling them

You'll have to look on their website