Hi Chuck, I am not familiar with this game so can only refer you to the walkthrough. It doesn't look to me like you can actually use the map in an interactive way, but we should wait for confirmation on this.
As far as getting to the hospital; here is the relevant portion of the walkthrough - this is after having received the map:
Go outside, and to the pier. Talk to the two men on the pier. “If you can swim, the ferry is safe, ok?” Nice to be in New York. There’s a rope and life preserver on the platform, but you can’t do anything with it yet.
Look at the bus station, and look at the poster. Funny. Use some small change on the binoculars near the pier (you can do this whenever you like).
Go to the ferry building entrance for a cut scene.
Arrive at the hospital gates and push the intercom, follow the nurse inside