Re: Passaic River/Hackensack River (NJ).
Yes.
I'm not well versed with the Passaic river but there is a very nice free launch and parking at Laurel Hill Park for Hackensack. It also dumps to NY harbor.
Depending on your craft, there are smaller launch sites for canoeing and kayaking. NJ is pretty good with that. If it's public land and legal parking, you can pretty launch on either river where you can find a place to put down your canoe or kayak. Larger craft is another story. They ream you with ramp fees.