for MIA try Lake Sch-Nepp-A-Ho, its right off the US 31 Russel Road exit which is the exit you take to get to MIA. You can see it from the express way on your left before you exit. It is definatly the closest camping site to MIA as far as I know since its only like 2 miles away. heres the web address to there site.
http://www.michigan-campgrounds.com/