I'm a Chicagoan and I love bike touring in Michigan where I have family. The summer of 2015 we made a loop ride leaving from our Wicker Park home and riding north to Manitowoc, Wi., where we took the ferry to Ludington. From Ludington we headed basically east mostly following USBR #20 before turning south at Bay City to the Ann Arbor/Grass Lake area. We then went mostly west around the south end of Lake Michigan and back to Chicago. The ride is flat-to-rolling with a couple challenging but not overwhelming, i.e. needing to walk, hills. This route took us about 4 weeks riding 30-35 miles per day. It also included a couple of rest days
I used ridewithgps.com to plan the route and like that they show designated bike trails/paths. Riding out of and back into Chicago was absolutely no problem using the designated roads/trails. The main issue was a lack of campgrounds between Chicago and Milwaukee forcing us to motel-it the first three days.
In 2014 we did the aforementioned ride up the Lake Michigan shoreline from Michigan City, In to Mackinaw City. The route has received the USBR #35 designation. The hills were more challenging than last year's loop ride, but still doable.
Michigan's state campgrounds are outstanding for the most part. Their Dept of Trans, as well as the Adventure Cycling Assoc., can supply routing directions for USBR 20 and 35. I used
Allstays | Campgrounds | RV Parks to locate campgrounds.
Have fun.