Plymouth CC is a rather low key club, they have tweaked a few tees and bunkers, added some drainage and tightened up the agronomy over the last ten years. From a playing guest perspective, perhaps that is all it needs. I think they are limited in tee expansion, but plenty of open land seems to border the course. When the prevailing Southwest blow kicks up and you are hitting a hi-tech 3 metal into a par 4 to a green that sheds golf shots, its a real handfull. Adding 800 yds to this layout would be too much.
Plymouth,Ma has added many new courses in the last ten years, including designs by Rees Jones, Nicklaus Design and Coore/Crenshaw which are all challenging but Plymouth CC is still highly regarded.
On the same theme, 1 hour away from Plymouth,in Providence RI ,we have the Ross designed Wannamoisett CC, built on a rectangular 99 acre parcel, this course is also a par 69.
Both these tracks have high level amateur tournaments, the aforementioned Hornblower at Plymouth and the Northeast Am at Wannamoisett. Both course stand up well to strong amateur fields.