Opinion (and just that) of one of those Massachusetts people (who doesn't know all the ins and outs of what's happening, just from this thread).
There are several landowners involved, DRED, TB, and the public in general. We on VFTT seem to view "the Ossipees" as a single unit (even acknowledging there are multiple owners.) I doubt the landowners see it that way...their primary concern would be for "their land" while trying to be good citizens. Someone needs to coordinate among all the interests on a regular basis. Then the public can have uniform expectations across the range and the landowners don't have to waste time figuring out who to talk with every time an issue comes up. At the risk of committing someone else's time, money, and effort, I suggest LRCT take point in some way.
There needs to be a hashing out of accepted behaviour. I agree with Roy that "no mapmaking" is counterproductive. And I don't see how we can get very far if anybody can close the property by posting a map online. But I hope anybody willing to put the effort into a map would be willing to accept resonable restrictions, such as only showing established trails accepted by the landowner. Plenty of people post here about cutting a deadfall (or sometimes much more, another topic...) on established trails. I can understand how a line on a map may attract people who think they should "keep the trail open."
Finally, how can we help address the landowners' concerns? Cleanup day? Volunteer for monitoring (like WODC does in the Wilderness on occasion)? Make a standard sign for places where people enter the Ossipees, a trailhead kiosk writ small, with information on respecting the private property? (and, of course, having us chip in towards such signage.)
But first, please, TB and rocket21, take down the map as a gesture of goodwill. For now, maybe replace it with one where the closed properties have been blanked out? It does not appear that archive.org has picked it up yet, but the longer it stays up the harder it will be to dislodge from the net. I don't think standing on our rights is going to make much progress now (right to publish, right to control access to the land...). I know the print run of the existing map is a financial hit, and I'm sorry I can't think of a good solution for that.