We parked at the small lot off Pine Cobble Rd and followed the route described in the book pretty much to the letter, so I won't go into detail about the geography. The one deviation was that we did tack on the mile or so out-and-back on the AT north to the Vermont state line, which was an enjoyable roller coaster ride along the forested crest of the ridgeline. At the trail junction on the summit of Pine Cobble we ran into and chatted briefly with a young thru-hiker who was "slackpacking" for the day; she was from the Northampton area and seemed in good spirits. Other than her, we saw very few other people out there.
After the summit we dropped down the shatterfield of cool white quartz(?) rocks to the actual exposed sub-peak that I think is Pine Cobble proper. We had the views out across Williamstown to ourselves, but there were a couple of really annoying flies that eventually forced us off the peak. The descent is initially a bit rough as you drop down the rocky section of Pine Cobble Trail, but it soon smooths out some and becomes quite runnable, especially once you pass the triple-boled tree trunk that always seems to have a small pool of water in it. I really love the final mile or so of descent along this run.
We capped the day off with a dip in the "pool" at Mohawk Trail State Forest (where the parking situation was a bit silly), and dinner and drinks out on the patio at the Cold River Cafe in Charlemont.