I'd hasten to add that the dress code for Campbell Apartment is more relaxed than it used to be; now they just ask that guests refrain from "wearing baseball caps, sweatpants, hooded sweatshirts, shorts or flip flops."

If you're going to Grand Central Terminal, also don't miss out on the whispering gallery, the oyster bar, and learning about the meaningful architecture through some sort of tour (be it self guided or the official one). Lots of tourists pass through Grand Central, but if you want to learn about "hidden" elements of NYC, learning all the secrets behind the symbols around Grand Central is a great way to do so.

Architectural Digest has a good review of many of these secrets for those interested in going in depth.