Lowered the FKT to 56:27 this morning, August 6. Completed the loop counter-clockwise. It's a perfect test for a short, all-out effort. Tight and twisty singletrack, nice hemlock forest, river-side trail for a couple of miles, nice bridges for the brook crossings, a nice stone staircase climb (if run counterclockwise) right in the middle, and just technical enough to keep you attentive. Good swimming in the Housatonic (or Lake Zoar, whatever you call it) afterwards.
Thank you Simon and Alex for posting and letting others find out about this nearby gem.
Pretty sure a speedster could still lower the time.