In the absence of anyone coming in with specific knowledge or experience with good reptile vets, I know the Foster Hospital for Small Animals at Tufts in Grafton has specialty care for exotic pets.

Though they are a top-tier emergency hospital, they also do regular veterinary work--checkups, maintenance, steady-state well-visits, etc.

I have personally witnessed many "exotic" pets there over many visits and years. The most recent and the one that stands out in my mind is the HUGE tortoise they were helping get outside on a rolling exam table with their human. It was big like those fuckers you see on TV. Put your arms out and make as big a circle as you can and that was this big girl.