I just took this twisty, beautiful drive for the first time in my wagon. I had driven it before in my old college beaters, but never in my WRX and I kinda forgot how nice it was. I was heading north through upper Bucks County on 611. It got nice and twisty right as I entered into Northampton County. You're right along the Delaware for almost all of the ride. The canal sits right beween the road and the river. The views are great and worth bringing a camera for. There are a few scenic view stops, too. There are only a small handfull of traffic lights to deal with for this stretch, with the exception of the city of Easton. The twists and turns between towns aren't crazy, but are fun for a little "spirited" driving.
Up there, there are towns so small that rely largely on state police to monitor the roads, so keep that in mind