I am in Northern MA and there are 2 that have been in business for years with good reputations..
One is Regan Ford in Haverhill, MA and the other is Nassar Ford in Lawrence MA..
Regan is where I bought my last 2 Super Duty's
Another option you might want to think about is Ford of Greenfield in Greenfield MA which is in the middle part of the state.. Contact BIGKEN on FTE and I am sure he can help you out..
I will PM him to let him know also..
Don't forget to join the NH chapter if you haven't already..