If you head right, or north on the Housatonic River, this is probably the most scenic avenue, but you can only go about a mile upstream before hitting the Derby/Shelton dam.
If you head left,then make another left to go north on the Naugatuck River, the river parallels the new Derby and Ansonia walking trails, but the views are non-existent due to the high banks of the river covered in rip rap which was constructed for flood control purposes after the Great Flood of '55. You may hit some rocky areas at the Bridge St. Ansonia overpass.
The 3rd option is heading left from the boat ramp, then turning right to go south on the Housatonic. I haven't tried this yet but you would eventually reach the Charles Wheeler Wildlife Refuge and Long Island Sound.
You're always within earshot of the sound of traffic. I was hoping for some interesting cityscape views, but views on the Naugatuck are largely blocked by dikes; the Housatonic is a bit better.