i actually liked cape cod beers hefeweizen and the people there were nice, british beer company in hyannis had a few pretty good beers when i was there too.
i am definitely going to hit Cap Cod Brew and probably BBC for lunch in Sandwich on the way in (too bad it is a chain)
There are a few threads on topic but a bit dated though you might find them helpful still. In the Dennis / Harwich area I hit Ring Bros, Yarmouth wine and spirits and Cranberry Liquors. All have decent options. Cranberry probably the best right now. Nearly all people recommend Cape Cod Beer thou my one visit there was meh in terms of experience. I do like their beers for what they are putting out.
100% and don't get me wrong, I will go back, just was a pretty normal brewery experience ... Nothing unique or one off at the brewery, just what they distribute for the most part.
Cheaper to go there and get your growlers filled at the brewery though. I agree though, I would like to try their winter beers.