Just did a short stretch of the D&R (between Stockton and Lambertville) a few weeks ago as part of a three-day tour from Port Jervis to Philly. Took the road between Frenchtown and Stockton because I need to make some time, but I have ridden the trail on numerous occasions.

If you ride it, definitely check out the pedestrian bridge between Bull's Island and Lumberville, PA. Nice views of the river, especially in the morning.






The section of the D&R (the feeder canal trail) to Frenchtown actually goes a little beyond Frenchtown to just outside of Milford. I wouldn't bother riding beyond Frenchtown though. The trail never reaches and ends abruptly in the middle of nowhere. That's because there is an environmentally contaminated area between there the trail ends and Milford.

If you want to try something a little more rugged, there is something called the Paulinskill Valley Trail:

Paulinskill Valley Trail | New Jersey Trails | TrailLink.com

It's in a beautiful part of the state.