The Des Plaines River Trail in Cook County has always struck me as something of a missed opportunity. While it runs near Chicago’s West and Northwest sides and has some lovely river views, it’s largely a dirt path that is pretty much impassible in damp conditions unless you have a mud-friendly bike. (Once you cross into Lake County at Lake-Cook Road, the trail is paved with crushed limestone, which is much easier to ride after a rain, and it goes almost all the way to the Wisconsin border.) There are also some access issues and disruptions in the route.