There's two bathrooms in Moyinhan that are nice, but only like 8 stalls. On either side of the food hall, one IN the food hall (mid 33rd street, lower level) and then one bathroom on the south side near Duane Reade (mid 32nd street).

There are bathrooms that are bigger in penn but during a rush they can get really busy. It's in the "big room" where the large timetable board used to be, SE corner of 33rd and 8th.

Than there's the tiniest bathroom ever in the NJ transit waiting area, probably not the best if you have kids because it's like 3 stalls.