So which bike should I take?

My wife wants to take the tandem. But her friend (who has ridden before) thinks we are nuts due to the crowds. I am fine navigating the tandem even in crowds.

We will probably take singles as well in case my wife changes her mind. In that case I am torn between my roadie (OCR C3) or my old Mtn bike with slicks. is a roadie ok for this ride? I haven't been to NYC in awhile and never noticed the road surface that much.

-D