Too cool! Wish I had the time to join you for part of the ride. I'm in Northeast Indiana, so look me up when you come through these parts. Here's my suggestions:
1. I would head up through Michigan (preferably along the West coast which is beautiful and has some very unique towns and great beaches), over the Mackinac bridge (stops in Traverse City and Mackinaw City), and through the U.P. (Sault Ste. Marie is a neat stop, as is Tahquamenon Falls...and maybe Escanaba in da' Moonlight - a movie with Jeff Bridges). Skirting along the Southern coast of the U.P. is also scenic.
2. If Chicago is really on the agenda for you (lots to see and do in Chicago, but ain't nothin' cheap), Rockford Illinois has one of the largest and really well done Japanese Gardens in the Americas - well worth the stop.
3. Riding through Southern Ohio and Southern Indiana is ALOT more scenic than cutting across the Northern parts of the states. There are a lot of beautiful roads in Southern Indiana around Nashville / Bloomington (and one of my favorite places to eat is at the Story Inn in Story, Indiana).
Ride safe, keep us posted as you start nailing downs dates, and post on the way!