The flow is anywhere from moderate to near none, but the way the river bends makes it somewhat interesting. Being suburban, there are houses and campsites along the way with a railroad bridge and a couple roads along throughout the trip. Once the river goes beyond the route 108 bridge, there is the Exeter Elms campground. From here on out we have seen hundreds of turtles, otters, beavers, and musk rats. This last stretch is possibly the best part of the ride.
We found that while taking our time, going from Powdermill to Gilman takes about 3-4 hours. If you are more interested I'm a shorter trip, you could also launch from Linden St. bridge (2-3hrs.)
The other option is to launch from Gilman park, paddle upstream, and return.