MilkCartonGoPro on 5/19/2021 3:42:12 PM:
I just completed the Pittsburgh to DC ride last weekend (Fri-Sun). The trail conditions on both the Gap and C&O were pretty much ideal (temps topped out low 70s and trails were dry). The Gap is definitely a smoother trail surface throughout, although it's a looooong slow climb to that Continental Divide. The C&O has some roots, small rocks, potholes except for the 10 miles ro so before Harper's Ferry and roughly 20 miles after Harper's Ferry where the trail has a similar surface to the Gap. I elected to take "advantage" of the Western Maryland trail to pickup some time and take a break from the natural terrain.
If you are taking a similar itinerary/speed/etc., then I highly suggest stopping at the Kickstand Kitchen for lunch on the Gap as there is really not much after that and it's right on the trail. We also stopped in Hancock on the C&O as there is a Sheetz right off the WMRT.
We didn't have any material detours on either trail, so all the major work appears to have been completed.
Last observation, the dust factor was an unexpected aspect of both trails. I highly recommend bringing chain lube, as my bike (and chain) were pretty well coated with dust from the trail after each day of riding.