Crossed the Riverton Bridge into McKeesport, and instead of crossing the Yough we stayed on the Mckeesport Loop. Stopped at Puzzler's Restaurant in McKeesport for lunch; much better than I had expected. I don't know why but I kind of expected it would be a dive bar, but it was a nice place for a meal, the food was very good, it had WiFi, the coffee was great; all my needs fulfilled. I had a Reuben sandwich, YC had the small fish sandwich.
Come to find out, the place is called Puzzler's because it focuses on giving work opportunities to students with autism, and the national autism logo is a puzzle piece.
Puzzler's Restaurant has a rear deck and a bike rack next to the McKeesport Loop Trail, across the river from the GAP. Really an excellent place for a sandwich if you're riding out from Pittsburgh. If you get the fish sandwich, stick with the small (which is very generous).
Departing Puzzler's, YC pointed out Zak's Bike Shop in McKeesport, which was a good thing because a few minutes later he had a flat tire so we walked over there. I got to meet Zak and see the shop, which he explains is the only bike shop between REI and West Newton.
Returned uneventfully, got back to the trailhead at sunset. A very nice ride.