What's strange is that during the five years I worked at BSS, no one ever used the mezzanine seating. It was considered a safety risk. I do recall reading somewhere that in its much earlier days, BSS had events open to the entire town- perhaps they used this seating back then.
One other thing about "Belchertown"- I grew up there and always knew it's name was a joke for many, but actually it means "good cheer". Bel (good) and cher (cheer). Also, that camp someone mentioned is behind G Building and not a long walk at all... if it's still there!
To Alex: Belchertown was named for the colonial-era MA governor, Jonathan Belcher. The town's original name was Crystal Springs, but supposedly the governor was annoyed that it wasn't named for him; hence the name change. And to Bob: As BSS slowly closed down the vast majority of its population went into group homes. Perhaps some of the more challenged/challenging people did go to other state institutions, like Monson.
I worked at BSS in the 70's and started out by volunteering at dances held weekly in this building. It was rather bland back then; decay has really given it character! I worked in C,D, F, G, and the infamous K Building, torn down as a symbolic act when BSS was still open. K housed profoundly retarded men. Any chance you'll be exploring any other buildings? Some are actually in use as town offices, schools, etc, but others remain empty. I love your site and visit it often.
Back in the 70's, when BSS was open, this building was known as the School Building. On the weekends, they'd have dances there. Usually they'd play records, but sometimes there were live bands. One I remember was called the Blue Max. Despite all the horror stories, those dances were fun; every single person was a true character and the dances were wild. It''s strange to see the building all boarded up and decaying, and all those people gone, all those memories fading away or vanished...
The school shut down the year before I moved to the area. Local papers published Belchertown school horror stories thoughout the 1990s. It was pretty nasty. It did not garner as much attention as Northampton State Hospital, but it was pretty notorious.