I went to college in Springfield; you'll pretty much need to head up to the Berkshires in the northwest corner of the state for the good stuff (Butternut, Jiminy, and Berkshire East are decent, and Bousquet is a charming old-time place but small). From Springfield you'd basically pick up the Mass Pike and head west, then take state highways north. The other nearby areas are kind of small (and/or no longer in business).
If you're headed back to PA that day, there are a couple CT ski areas that would sort of be on the way, or at most a short side-trip: Ski Sundown and Mohawk Mtn. Both are only about 600-700 ft vert and fairly small -- local community type hills. Might not be worth it.
I'd probably bite the bullet and head to the Mass. Berkshires if it was me. Or even backtrack to Mt. Snow, it's not that much farther. If the weather is good or you are comfortable driving on back roads if the weather is not good, this is a great shortcut to Mt. Snow:http://maps.google.com/maps?f=d&hl=e...1417&z=10&om=0
That shaves 30-40 minutes off the drive compared to taking 91 all the way to Brattleboro and then cutting over.