NN has always had sort of a no-frills feel, and it is a pretty good golf course with some features you don't see every day playing your normal CCFAD. The crushed-shell paths are a nice touch, and the whole place feels like you are playing in someone's paddock in back of a farmhouse. I hope the elevated greens fees don't turn expectations towards too green and perfect. You'll read many reviews (including the course website) that says it's a links, which it isn't, but I'd call it a wide-open parkland with links in mind.
NN used to be an every-year visit in March for me when the temps first hit 50 degrees and I needed to dust off the clubs. Fees were discounted, and it's just close enough to Boston early morning without traffic (~1h) that it totally works. I just haven't been back in a few years.
Great to hear they are adding a 3rd nine...hopefully it leads to a fourth too!