Riding with traffic is extremely dangerous but if you have skills and common sense you will be ok. Nothing compares to riding around Manhattan. The city never sleeps and a bicycle is the best way to see the sights. You can ride through Riverside park by the Hudson river all the way down to Battery Park and then back uptown on the FDR Drive. Along the way you will see breathtaking views including the USS Intrepid, the Statue of Liberty and the Brooklyn Bridge.
Central park has some trails and lot's of rocks, drop offs and other technical stuff.
On or off the bike, 24-7, the fun never stops. Five stars for the capitol of the world. Ride wherever the little voice in your head tells you to go. Sure, there are places you can ride safely, like central park. The Brooklyn Bride is short, but you can't beat the view and you get a couple of fair climbs and descents if you go over and back.