Share 'Favorite autumn rides'

It's Halloween, it's Halloween, it's Halloween! (The Shaggs, 1969).  I can feel my favorite season creeping in, something about the cool air in the mornings and evenings.  Does anyone care to share their favorite fall bike areas, routes, and trails, in the Chicagoland area or anywhere else?  I'm always looking for things to do and places to go in southwest Michigan, for example.