Here is a quick link to the thread from 2012 which has some good info, including road closures, most of which is still relevant:
Battle Creek air show
The law enforcement agencies working the event usually use one of the countywide non-encrypted TG's for event traffic.
As I get updated info, I will post it here ASAP. I will be going to the airshow at least one of those days, since I have the whole weekend off this year!