When I was working in NYC as a mover, I was often in and out of buildings overlooking the Hudson. You're right, as far as Manhattan goes, its quite calm & peaceful!
If you really want serenity in NYC, you have to head to the outskirts - Long Island, Far Rockaways, maybe Corona Park-Flushing Meadows in Queens.
Even Coney Island (shamless post-promotion!) feels like an escape!