Road trip from Austin, Texas to Portland, Maine. What breweries are must see and what local beers should we be looking for?

The idea is a 2 to 3 week road trip to visit the Northeast this Spring. My girlfriend and I have family in along the way in St. Louis and Cleveland. The bulk of the trip is to be spent in the Vermont, Maine, Massachusetts area. I know that Great Lakes in Cleveland is a must but would really love some suggestions or input especially since I'm completely unfamiliar with the region.