I have, I have with arms waving wildly in the air while jumping up and down.

Oh wait, but not on a FG/SS but rather a touring bike. I don’t remember shifting though.

I was using Continental 4-seasons in 28mm and I don’t think I would try anything narrower. Yes the trail is virtually flat. I rode approx 50 miles in the Fort Frederick State Park area of the trail. The surface was very fine gravel to packed dirt for the most part. I am unsure as to the surface in the more eastern parts of the path. Your Mountain bike or Commuter may be more appropriate due to tire widths.

fwiw