There are at least 4 RVs in Plymouth KPYM.
Jose,
Russki is low in his guess. I just counted six in my head. We did have one fly the coop a couple of years ago. But you are right as well. Very few by most counts.
I attribute this to the fact that New England is far from an aviation "MECCA".
Seems like it has been that way since the birth of aviation. Historically there have been a few events like Amelia Earhart being from Medford, MA and Lindy visiting a few times. Aside from that airplanes have been not part of the areas infrastructure.
I am guessing that unlike say, Alaska... you can drive most places easily. Likewise, unlike the midwest, the land isn't conducive to flat fields to land in. The cost to live here is high and totally not worth it, therefore land is expensive. There are also more and more city slickers, accountants, politicians, pencil pushers and business men and less and less farmers, tinkerers and mechanical people.
Combine all this along with generations of people not taking to the skies and you don't get airports and planes. Hence, less RV's...
Unfortunately for me, I have lived here all my life. In those years I have pondered the same question and that is what I surmised.
I have been in the process of putting my new engine on the airframe and spending some time at the airport lately, if you care to stop by sometime and chat. Shoot me a text to set up a time.
John