I used to live in the Detroit area, and that is the area that I know the least about. I think if you can hit Jefferson Avenue it will take you south out of Detroit and eventually to Toledo. We did go part of the way on one of our trips to visit family, but never got north of Detroit.
My wife and I cycled across the US a couple of yeas ago, and it took us through Toledo and Cleveland. We were following US Highway 20 from Oregon to Boston so we tried to stick pretty close to it. Toledo was not a problem at all, but Cleveland was a challenge. Cleveland has been hit pretty hard by the recession,and the town shows it. We just used a city map and fumbled our way through. We went through some pretty "sketchy" neighborhoods, but the people we encountered were really great. It is amazing what kind of response a smile and a pleasant greeting will get. We did stop at one diner, and the waitress told us to bring our bikes inside " if we wanted them to be there when we came out". A Doctor who invited us home for lunch that day in the little town of Elyria told us our route would take us through "harcore inter-city" I did not read between the lines.
I'll see if my wife kept the map we used and will PM you the route details. She did produce the map and Journal, and if you are interested let me know
55 th Street Diner
Geneva State Park-- A great place to camp!