The proper name for this road is Henry Hudson Drive, but we in the NYCC and the rest of the NYC cycling world call it River Road.
This is one of the outstanding gems of NYC cycling. The first time you do it you will be floored at the improbability of such a first rate cycling experience sitting just outside the city's door, literally. Set into a near vertical wall (and in some places, really in a vertical wall), it is ensconced between the Hudson's water edge and the cliffs of the Palisades. And, should you be a strong cyclist and on your game, you can cycle from Midtown, do a round trip, and return in under 3 hours.
As this route parallels 9W, it can be done as a one way with a return on 9W back home, vice versa, or you can continue on to Piermont/Nyack.
The 3 significant ascents on the route are not totally accessible to cyclists. We are not allowed, by law, to take the Englewood Cliffs climb beyond River Road proper. This hill actually ends on Palisade Avenue but the section to it is verboten! Thus I call it the "Forbidden Hill." But its real name is Dyckman Hill. Traveling south to north on River Road, this is the first climb.
The middle ascent ends just north of the "bridge over the waterfalls." As it is the easiest of the 3, Ron Roth calls this grade "honorable mention." Don't let the name fool you, it gets steeper in the second half.
First place among local climbs is the steepest and longest ascent on River Road, Alpine Hill. Consider your performance on this ascent as a good a barometer gauging your hillclimbing ability as anything else. Many do hill repeats on it, taking it from the boat basin on the bottom, circling the flagpole at the station and going back down.
Should you desire to challenge all hills on the ride, add a descent and return down Ross Dock, at the first traffic circle. Adding Ross Dock adds 0.6 mile round trip. Certainly do the Alpine Hill from the boat basin to get the full measure of the climb. Including the section down to the Alpine Boat Basin adds at least 0.7 mile round trip.
Vertical gain off my Polar 710i (an ancient device, but reliable) gave me 880' going north with Ross Dock and Alpine Hill from the boat basin. The return was 600' from the Alpine police station, not going down to the boat basin or Ross Dock.
See Regional Hill Grades, in the Resources section of this website for specifics on hill grades:
Water and restrooms, bike rack outside, are open year round at the police station. The water fountain has a bottle filler!
Restrooms at Ross Dock are closed in winter. There is a telephone and vending machines with water, soda and candy.
Englewood Cliffs Boat Basin restrooms may be closed in winter. Its Snack Shack is closed in winter.
Undercliff Picnic Area, between Englewood Cliffs Boat Basin and Alpine Boat Basin, has Port-A-Johns in warm weather. But certainly no water.
Alpine Boat Basin restrooms may be closed in winter. It has a soda vending machine.
Notes of caution:
1- The southern entrance to River Road is quite narrow and curved. Keep right; there is 2 way traffic.
2- For the most part the surface is good as of this writing. But there are places where the surface is broken. In poor light, rain, leaves, etc, a cyclist could get into serious trouble on a rapid descent. Observant, regular users tend to know where the dangers are. Just because a cyclist in front of you is pushing the limit, do not assume you can do likewise.
3- At times sections of the road are chained off by the Palisades Park officials. Especially off season. Chains fully blocking the road are placed at entrances to the whole road or sections. Some of these barriers are at the bottom of descents! If the gate is closed on entering, you can pass thru between boulders, carrying your bike.
4- As of this writing (11/6/15) the section with the worst surface (worst being a relative term; it was not very bad in my opinion), is between the Forbidden/Dyckman Hill and the Alpine circle. Exercise caution.
River Road is a quinessential NYCC experience.