We went on 30th Nov '16, everything seemed to happen that weekend, Rockerfeller lights, Saks etc. It was amazing. Too many people for dh's liking, the Saturday night 7pm coming out of TOTR was a bit like being lost and crushed in a crowd we didn't think it through.
You must do the Highline, it's one of my most favourite parts. We were there for 6 days and had brilliant weather, cold but dry and clear.
We stayed in the financial district as it was quiet over the weekend and there was a tax we didn't have to pay as we were out of the tourist area. It was also quieter on an evening. Walking distance to Battery Park.
We booked one of the passes and used it for Empire State, TOTR and Ground Zero museum (which was amazing, so tastefully done). You don't have to pay full price for Nat History Museum, you can make an offer (you have to queue for a teller) and we paid $10 each as only had 2 hours to spare. TBH I wish we hadn't bothered as we didn't find it any more amazing than London but we did then walk down back past John Lennon's home and through central park.
Oh I could just go on about it for hours.....