I've done many sections, but not all, and not the whole thing at once. It's actually a "V" shaped trail...one terminus is in East Brunswick, the bottom of the V is in Trenton, and the other terminus is Frenchtown, NJ, along the Delaware river. I've done the following stretches:
East Brunswick to 6 Mile Run
6 Mile run through Princeton to just outside Trenton
Frenchtown to Lambertville
Lambertville to Washington's crossing.
I'd say the most scenic stretches are along the Delaware (the latter two above).