This route definitely has significant urban traffic -- though many miles of it can be avoided by taking bicycle paths and walkways (which have hazards of their own). It also has some riding on a road with no two lanes of traffic in each direction and no shoulders.
Because of the traffic, we recommend doing this route early in the morning on a weekend day. We recommend against doing it on a weekday any time near morning or afternoon rush hour.
Some special points to consider . . .
Route 505 through Edgewater NJ
One section whose traffic pattern we do not like is Rt 505 through Edgewater, with two non-wide lanes in each direction and no shoulder. If riding on a weekend, we like to plan the route to get through this section early in morning when there is usually less traffic.
Off-road paths and walkways
A different kind of traffic interaction to consider is that the various off-road paths in Manhattan and New Jersey now get lots of non-motorized traffic (walkers, skaters, runners, bicyclists) especially on weekends and on pleasant weekday evenings. Sometimes you sometimes might find that getting off your bike and walking is the only reasonable way to proceed. This is another reason to start very early in the morning on a weekend.
If you want to avoid this special off-road traffic, be prepared to find an alternate route on the streets. Another alternative is to use the subways or buses to help.
For some ideas about riding on the streets as an alternative to the West side path in Manhattan, try some of the links at Getting Around in NYC with a Bike. The NYC Dept of City Planning has some maps that show recommended streets for bicycling. For some related ideas, see the Reports.