there is tubing & kayaking rental on the Boardman River. Another highlight IMO of the Grand Traverse area is to go to Sleeping Bear Dunes National Lakeshore park: http://wikitravel.org/en/Sleeping_Be...onal_Lakeshore

A nice feature about western Mich is that it is on the far western edge of a time zone so one gets plenty of daylight during the summer hours. Plus sitting on a beach (of which W Mich has plenty of) on a warm summer night and watching the sunset over Lake Michigan is heaven.

I've camped a bunch of times in Brown County State Park in Southern IN, a great park as msko06 states. we've never been to Turkey Run but have always wanted to.

The best wineries in the midwest as DavidDTW mentions is the Niagara region.

Have fun, sounds like a great trip.