I've waited less than an hour in New Jersey and Connecticut.
When I still lived in NYC, I resolved that if I needed a hospital but I wasn't in extremely bad shape, I would drive an hour into an adjacent state's ER rather than wait in NYC.
Coming in via an ambulance doesn't trigger some sort of re-prioritzation, if you're not suffering from something that is immediately life threatening.
In most NYC hospitals, you will end up in a secondary waiting area that lies just beyond the regular ER doors.
Good luck if it's a Saturday night.