Congrats on your new job! Love the BBG. Went often to admire that incredible wisteria bonsai (when it's in full bloom) they have in the greenhouse. If you go during the cherry blossom festival, it should be in full bloom so definitely check it out.
If you haven't been, I highly recommend:
The Frick Collection
http://www.frick.org/
The Cloisters
http://www.metmuseum.org/visit/visit-the-cloisters/
Definitely do the audio tour, especially at The Frick Collection, as it used to be a private collection/mansion turned museum.
If you have time, I'd also try some B-way lotteries before you go! It's the best deal in town (if you win, of course) and it's one of the greatest perks of living in NYC.
