Hotel points are rarely a good value in NYC, especially over weekends. I'm not sure exactly how much prices fluctuate during the peak summer tourism season, but I haven't paid more than $100 a night for all of my weekend stays since August.

Might be worth mixing paid and cash for this.

Redemption costs for NYC hotels are also a complete waste most of the time -- think 70,000 points for a Hilton Garden Inn that is going for $150. There are also some Hilton codes that can bring down the cost substantially. I'd make a refundable reservation and watch it 2 weeks before the trip and see if the price drops, which it probably will.