I lived out there as a kid, and I have to tell you that it's very rural in that area. I was often bored to tears. But you should be fine for only 6 weeks.
Brimfield is very close to Sturbridge, so I'd definitely go to Old Sturbridge Village. http://www.osv.org/
I also love a lot of the apple orchards in the area. I recommend Brookfield Orchard, personally. They've got general store with penny candy, fresh baked pies and dumplings, etc. Plus there's apple picking and a playground.
Further west are a the 5 colleges: UMass Amherst, Amherst College, Hampshire College, Mount Holyoke College and Smith College. There's all the stuff that goes with college towns, and the campuses are beautiful.
East is Worcester, and the Worcester Art Museum among other more metropolitan attractions.
Good luck and have fun!