The first 12 miles of the path were muddy and bumpy. It is like that all the way to Pittsburg - so be careful NOT to go when it is rainy.
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I've ridden all sections West of Lees Ferry both ways
1) its Pittsburgh (Pittsburg is in kansas)
2) not exactly true C&O is like that all the way to Cumberland but Penna. portion of GAP trail uses a pea gravel so it drains pretty fast vs C&O being basically the clay based historic mule trail
3) 10 miles either side of Hancox is a paved trail running parallel to C&O so there is an option to get off
the dirt for 20 miles
4) It seems like the rough trail surface is typical for MD. NCR trail (Hunt Valley, MD to York, PA) MD portion is rough like C&O, when you cross PA line one finds sweat pea gravel