As the title says we're leaving for Michigan this weekend, specifically the Mackinac Island area. I've looked through a number of sites in regards to Michigan laws and am aware that I need to disclose to a LEO that I'm carrying and where the prohibited places are. My main question is whether prohibited places are required to be posted, so I don't inadvertently walk into one. An example is a restaurant that may or may not derive more than 50% of it's revenue from alcohol sales or federal land or structures which may not easily be recognized as such. Is there anything else I should be aware of, such as on Mackinac Island?