I can loan you my copy of Rubel's Western Massachusetts map. Central has been long gone.
Check out some popular rides for ideas that can help you stitch a route together. One that can get you pretty much across the state is the High Point ride from Lexington to Mt Greylock. From there, I have used a route to Great Barrington. And then find your way to Hillsdale.
Check out the Strava bicycle heat map for alternate ideas.