Repeated climbing, not one crux
There is no single defining climb here the way there is on a lot of NY mountain ultras. Instead you get four legs of rolling terrain with climbing stacked up over and over, and depending on which source you trust that adds up to somewhere between roughly 4,700 and 6,700 feet of gain across the 50 miles. Treat the true number as a range and pace off effort, not off a single figure you saw on one site.
The carriage roads make the climbing more manageable than singletrack would, wide and graded rather than root-and-rock technical, so you can hold a steady hiking effort on the ups without fighting the surface at the same time.