Actually, in looking at the flight track for AC-712, that lost lamb must have been somewhere up over the Catskills or something... wonder if he ever made it down to Baltimore? Maybe somebody can dig up the archives and find "Bravo Golf" somewhere on a track down because that should be really interesting, likely comedic listening.
I don't have time, but I would start with Potomac APP on 124.55, though I can't imagine how he could have been in that dense area and only get a response on guard channel from an airliner hundreds of miles to the north.