Combining these two history-laden bicycle byways allows long haulers to chart a 334-miles course from Pittsburgh to the nation’s capital and in the process they’ll glimpse the Cumberland Narrows, cross the Mason-Dixon Line and the Eastern Continental Divide, navigate several state parks including Ohiopyle, bob along three rivers and the C&O Canal (also a national historical park), top the 101-foot-high Salisbury Viaduct, brave the pitch-black Paw Paw Tunnel (don’t forget a flashlight!), and admire Georgetown’s lovely brick townhouses. The GAP was the first inductee into Rails-to-Trails Conservancy’s Hall of Fame. Cottage industries of feeding and lodging GAP goers have sprung up in the many Industrial Age enclaves that used to be at the heart of coal and steel industries. Go in October to capitalize on prime leaf-peeping opportunities.