You could leave a message for Eric, he lives in New York and would be well qualified to advise you, he hasnt been on since May but I'll nudge him on Facebook and tell him to get his ass back on here to help you
Did someone say my name?
Hi there, 6stringer. Yeah, I'd be glad to offer any advise you might want. Just drop me a line and I'll give my best answers.
As for that time of year, I'd come anywhere from mid-May to June. It could still be swampy, but July-Sept is guaranteed to be a humid mess (though as I type, it's quite autumn-like outside). Besides, in mid-May you'll be able to watch a match at 11th St. with LFCNY.
It's gonna be expensive, too. This is an expensive city, but it also provides a lot of free entertainment in the summer, so that might be worth considering. I wouldn't advise trying to save money by staying in an outer-borough (though there are few deals to be found there, too) or New Jersey. Stay in the city (Manhattan) because you're gonna waste too much time with travelling as it is.
You'll find no shortage of great dining no matter what your preference. Just a matter of figuring out what you might like to eat first. I could certainly give more than a few recommendations. As for bars, we've got a ton. Again, it's a matter of taste.
Attractions. Tough one because many native NYers have never even done these. And if they have, it was when they were a kid and it was for a class trip. I'm sure most of these things are great, but all I see are long, annoying lines and a bunch of tourists (no offense). I like the idea about hitting gigs, a Bway show (go through tkts) and restaurants. That's my speed. We've also got some great museums. Some are easier than others to get into and around. The Met would be a good shout. MOMA can be a bit tougher. Plenty of small galleries. A great resource to you would be TimeOut New York. A solid and complete list of everything that's going on. And it's cheap.
Agree with Yank for the most part. If you're interested, Yankee Stadium is a spectacle, but pricey. It's easy to get around north of 14th St. (and some pockets south of there), though the East-West can be tricky when looking for a house number, if you're not used to it.
It's really a matter of what you're into. You can tailor it to be about what interests you. Any questions just PM me and I'll jump on here.