The Weehawken Waterfront is located on Port Imperial Blvd. in Weehawken Township, NJ just a short distance from the entrance/exit of the Lincoln Tunnel. If you're coming from New York you can take the first exit out of the tunnel for Weehawken onto Park Blvd. and follow a few quick turns through the local streets. Parking is available at the waterfront.
The Weehawken Waterfront is also accessible via public transportation. According to Google Transit directions, the NJ Transit bus stops within walking distance. I drove here; I haven't taken public transportation around here and don't know what the safety of the area is like.
The park is open from 7 AM to 10 PM. In addition to the walkway along the Hudson River, there are a few athletic fields. You'll run into a lot of joggers, cyclists, and other athletes.
Security has a pretty tight watch on the area. I watched two photographers try to hop the fence to get a better angle from down on the rocks, and they were chased down within seconds/minutes.
The Weehawken waterfront has a direct view of Midtown Manhattan and the Empire State Building. You can see pretty far uptown and all the way downtown. Here is a wide angle photo showing the entire view:
The view of the Midtown skyline is where this area really shines. The park is even with the Empire State Building. Your basic 24mm or equivalent wide angle lens will take in most of the view, and a medium telephoto lens around 200mm or more will bring you right in close to individual buildings.
Sunset is of course one of the best times to visit this location. During golden hour the sun will be behind you, casting a soft front lighting onto the skyline. In the morning the sun will be rising behind the skyscrapers creating a backlit situation.
This is tripod territory, especially if you are shooting at small apertures. A camera that handles noise well at high ISO will let you hand-hold many different types of shots up until the sun goes down, but afterwards it quickly becomes long exposure time. I don't know whether tripods are officially allowed, but nobody got on my case for using one. And with a view like this I'm sure people bring tripods out here every night of the week.
If you are looking for a nighttime view of the Empire State Building, or a different type of sunset skyline shot than the backlit scenes visible from Brooklyn and Queens, check out the Weekhawken Waterfront in New Jersey.