Most of the stream is flat and shallow besides 3 or 4 class I-II sections, 1 non-runnable dam-6' drop onto sharp craggy rocks-portage on river left, and a big honkin log jam very close to the put in-get over around or through any way you can.
If you really want to you can hike the trail past the jam. the Paulinskill is teeming with wildlife, you'll see waterfowl and painter and box turtles the entire length of the river, if you're really lucky you may come across a few fox too. The pool near the take out has some pretty big large and smallmouth bass.
I usually park at the take out and paddle upstream as far as my arms will let me. Going down river there is a fork in the river about halfway down TAKE THE RIGHTHAND FORK - the left will bring you to an old dam with only a 18" opening.
Oh yeah, a little ways past the bridge (traveling down river) is a horse farm on river left, these people are not friendly, don't stop here unless one of your friends needs help.