I'm not sure how much FAA regs have changed since the 27 years we flew, but we did have both FAA and landowner clearance to fly in The Meadows, just south of the airport. We were off the take-off/approach flight path, so maybe that helped. We flew in an area that was primarily potato field, so it got the name "Cape Spud".
There's lots of good POTENTIAL fields in the Northampton area, but of course the challenge is getting permission to fly for an organized group. A lot of the space is active farmland. This is one field that's caught my eye for years, but I suspect it's parceled out and that may make land owner permission an issue:
The area you listed in your post is 115 miles / 2:15 West of Amesbury.
You seem to have a good understanding of the area. Would you be able to approach a land owner? Even if we only had two launches there per year, it would be worth it. It would give us an opportunity to fly high power without having to travel too far.
I started working in this area at the beginning of February and I can agree, there are a large number of good sized fields that are just begging for a launch pad. As most of the fields are active farmland, getting landowner permission may be difficult. I'm not sure if UMASS owns any of the farmland, but that might be a route to consider.
I don't know much about farming so maybe Guy can chime in.
Perhaps before the crops are planted and after they are harvested, we would be able to use a farm area. As an incentive, maybe we can offer a farmer a cash gift to show our appreciation.