When will a county in Massachusetts vote for the Republican candidate?

[Skill and Chance]

Plymouth will likely vote for the next Republican who wins nationally, unless they are a huge SoCon.  In a reverse 2008 environment, Plymouth, Worcester and Barnstable would all flip.  There is a growing rural/urban divide in MA even though the state as a whole isn't shifting.  Also, I'm not sure if Clinton would play better/worse than Obama in those places.

[Skill and Chance]

Plymouth will likely vote for the next Republican who wins nationally, unless they are a huge SoCon.  In a reverse 2008 environment, Plymouth, Worcester and Barnstable would all flip.  There is a growing rural/urban divide in MA even though the state as a whole isn't shifting.  Also, I'm not sure if Clinton would play better/worse than Obama in those places.

I would change that to parts or the eastern half of the state.  That certainly isn't the case in the Berkshires.

Or anywhere west of the Worcester Area/ North of Springfield, really

Which means only 8/9ths of the population of MA is in the area with a growing rural/urban divide!

[Skill and Chance]

Plymouth. Then - Worcester. Then, probably, Barnstable, which is somewhat more socially conservative then fiscally conservative  (but, generally, socially moderate or even liberal) Essex. Then - ... probably nothing..

Is Barnstable really that socon? It has Provincetown and stuff...

Not so much by national standards. But at least somewhat - by Massachusetts's. And yes, it includes Provincetown (4th district, represented by Democrat Sarah Peake) and so on. But it includes relatively conservative areas (look at 5th Barnstable, represented by Randy Hunt, for example) too. Essex, while being somewhat fiscally conservative, leans (mostly) very moderate socially. May be - because of number of "upscale" areas.

Essex is complicated because you have largely libertarian Boston exurbs paired with the populist fishermen.  In terms of number of votes, the exurbs win, but it can produce strange results.