United States
Get the NYC DOT bicycle map (download or free at bike shops). Also note DOT has information on bridge closings. Sometimes if a bridge is closed they have a free van service. Stick to the paths on the map, watch out for pedestrians, and car doors. Good luck.
www.bikeforums.net is a good source of info. See info on avoiding bike theft. Hint: get a strong U lock and take the seat post with you.
Consider buying a folding bicycle in NYC and returning with it. bfold.com, nycewheels.com and others have folding bikes. Strida would be a good bicycle for touring NYC. Dahon make very nice general purpose folding bikes. Folding bikes can usually be brought on the subway and trains. A bit iffy on crowded buses.
I've just come back from New York, and my locks on my case were broken by the customs people there because they thought my case was 'suspicious'.
I've since heard that you need to have a so-called Travel Sentry Lock (TSA Approved) for travel to the USA.
These allow customs officials to open your cases without breaking the lock and they can secure your bag again after checking it.
Wish I'd have known before because I need a new case now!. I've just bought six for my family from a website called www.tripneeds.com they have these locks quite cheap.
I think Amazon also sell them as well, but they cost more.
Take my advice and get some of these locks before you travel to the States - it's worth it!
Send your feedback or queries to been.there@guardian.co.uk
Search Been there
Your tips about New York