Hello Futura- I guess from the lack of answers here, there are no specific $$ or tax benefits with living in Newburyport. I am not aware of any, and I did do some marketing for a real estate developer in the Newburyport area a couple years back- for a 55+ community.
I didn't know of anything to entice a senior to the area, other than the harbor area and the nice restaurants and galleries, etc.
Let me know if I can be of help somehow. Thanks and good luck,