I think its Hammersley Hill in Pawling, NY, just West of Quaker Hill Golf Club...
Like Quaker Hill, HH was part of Lowell Thomas' estate fiefdom in the 40s and 50s. It is now privately owned by the Seagram heir, and has been on the market since 2009, according to this site, which dovetails with what others have been link-posting:
http://www.jameslist.com/real_estate/united-states/new-york/new-york-the-best-kept-secret-in-the-northeast-us-451029Also, the listing on this particular source places the property and hole painting squarely in NY, not NJ or CT, so those can be eliminated.
I think the difficulty/confusion/uncertainty is for a few factors beyond the close-to-the-vest details:
1. It was 6 holes when first designed by RTJ in 1944, expanded to 9 some time later BUT had super long Par 7.5/8 holes among its nine, and has quite enough property to have been envisioned as 18 by the listers. This "kooky" feature is a little more fluent when you consider Thomas' other track, Quaker Hill, which -- though only having nine holes -- plays as a near true 18 from divergent sets of back nine and front nine tees. Obviously Thomas was into the fluidity of par and the concept of a repeatably "fun" hole.
2. I'll bet the few bucks in my wallet that the listers have confused Robert Trent Jones the Architect with Robert Tyre Jones Jr the immortal player hence the "world's most celebrated international players" comment.
3. Although No one ever plays it and most distinguishing features are grown over, the property manager still mows 85 acres of it and pathways of holes, if not greens, are readily seen from aerial maps.
I'm not 100% certain this is it, but I'm like 92% it is.
cheers
vk