I think you need to figure out what “feels” like a vacation to you. Although I’d have fun in the city, it would not feel like a vacation to me. There’s a website you might want to check out called Time Out New York (www.Tony.com). They also have one for kids called tonykids.com. It lists all the different activities in and around new York (Tri-State area included) and divides it by day trips, weekend trips, free events, festivals etc..
You might find something there.