Jimmy,
As you probably recall, I bought my baby in Mattapoisette. The lady that I bought it from had it in the water but never registered it. It still bore RI tags, several years old. So, numb as I was, I bought it. Then I bought the trailer from Quincy, modified it to fit, registered it and dropped it off to be loaded. I got her home in December, then tried again to get the title. It was a month long hassle. Emails and phone calls, messages left , messages ignored. Finally, in desperation, my wife went to city hall to see what we could do. They clerk said "Maine doesn't require a title on boats." So, she came home all set for the next year.
I think if you buy the trailer where ever, and register it in Mass you're good. I don't believe you need to have it inspected to register it so just give the DMV a bill of sail (hah!) and the serial number (or claim it's home-0built from salvage). They want your money. Then carry the plates down with you. Make SURE that the title is there when you pick up your new mistress. You should be fine.
So . . . what is she? I won't tell!