The shaded hiking-cycling path runs alongside a waterway built in the mid-1800s to transport goods to West Virginia. Step on at Jefferson St for a lovely escape from the crowds. Note the canal and environs are being restored and enhanced over the next several years, so you might run into construction along the way; check the latest before setting off.
In its entirety, the gravel path runs for 184.5 miles from Georgetown to Cumberland, MD. Lots of cyclists do the 14-mile ride from Georgetown to Great Falls, MD. The tree-lined route goes over atmospheric wooden bridges and past waterwheels and old lock houses. It's mostly flat, punctuated by occasional small hills. The park's website and Bike Washington (http://bikewashington.org) have trail maps.
The visitor center was closed for renovations at the time of research.