Here's another link for Chicago area routes/paths from a former Chicagoan and still frequent visitor:
https://fpdcc.com/places/trails/#north-branch
My favorite ride has always been the North Branch ride. I always lived in the City, mostly on the NW side, and I'd pick up the trail at Caldwell Woods (parking there) on Devon and Caldwell (at about Central). It goes north, all paved, to the Botanic Garden in Glencoe, IL. Round trip is about 32 miles, though you can pick it up at other locations, and do whatever portion you like -parking at various locations along the way. Most of the path is through forest preserves. Though you do cross several roads, all are easy, most barely noticeable after you do it a few times. There is a jog at Touhy where you may encounter some traffic and want to walk the bike across; all else is easy. Actually, Touhy was a favorite pause for me because there's a great hot dog place right before you cross North. Nothing like a Chicago dog and fries to fuel your ride, of course -although we're probably in Skokie there. Another favorite ride is the lakefront, of course, and you can also ride that a long way or many parts of that -again, all paved. For gravel, the Illinois Prairie Path can also be a nice long ride. I've done it from Wheaton to St. Charles, though I've also taken my bike
on the train from the Wheaton station to St. Charles, had lunch there, and ridden back. Link:
Trail Map - Illinois Prairie Path
BTW, Bicycling mag rated Chicago the top cycling city in the US in 2019 -or was is '18? It surprised, if not shocked me, but the city did make some impressive gains in prior years, and there are many excellent routes, in and around town.