Maryland:
C&O Canal Towpath Trail between Washington DC and Cumberland (185 miles)
Pennsylvania:
The Great Allegheny Passage (GAP) from Pittsburgh to the C&O at Cumberland MD (150 miles; 335 miles total for C&O + GAP)
Georgia/Alabama:
The Silver Comet Trail from Smyrna (northwest of Atlanta) to the Alabama state line
and Chief Ladiga Trail through Alabama to Anniston (total 94 miles)