The portage around the Shawville dam is a royal pain in the ass. They are supposed to decommission that plant by 2015 (currently listed as the second dirtiest power plant for emissions in the whole US). Once that thing is gone we figure they will take down the dam (which is modular steel that they move periodically for maintenance). Watch yourself along 879 there.
You'll be going past our place about 40 minutes downstream of Shawville, where the powerlines cross over. On the map it's the farm at the very end of Egypt Road, along the east bank of the river. When his son does his annual old college buddies reunion campout there every Memorial Day they put in at the farm and float about 3 hours. I've forgotten the name of that takeout they use (I will find out) -- it's a Game commission site and the Fish Police there are pretty merciless. Make sure your ducks are in a row if you land there. They gave one of the kids a $75 ticket last year because, though the 12 canoes had 30 PFD's for 30 paddlers (stashed in the hulls, which for some ungodly reason constitutes "safe paddling" here in PA), somehow in the scramble to get back in the water after they had to pull ashore during a short thunderstorm, one boat had 2 paddlers and 3 vests and another (which the hapless guy was in) had 3 paddlers and 2 vests.