Take Lucky Star or Fung Wah. You give them $15 (which I think may even be round trip), get on at South Station, take the bus to NYC Chinatown, do your thing, then come back. Really cheap, relatively quick (4 hours?), and your bike won't burden you while you're in NYC.

I took Lucky Star in February and really enjoyed it. They even have decent wifi on the bus, though you should ask for the password beforehand (I had to guess it - it was something like luckystar then the bus number).

Mode of transportation has not yet been determined. Possibly bike, possibly train, possibly bus. It feels strange not needing to buy plane tickets.

You lucky stiff! I have to go through this silly border control thing. mumbles something unintelligible

Good luck dude. I certainly wish US border controls weren't such a pain. (Having been to the UK several times, I think I have a fair idea of what it's like to be on the receiving end of at least similar measures.)