OS,  we did a 9 day float on the Copper River last August w/ out Scout Troop.  What a great experience.  We saved some coin by flying into Anchorage vs. Fairbanks, our rendezvous spot, and took the savings and an extra day to ride the Alaska Railroad up.  It was a nice, scenic 12 hour ride.  The Copper is also very silty - 1:6 silt to water ratio, I was told.  The reds and silvers were running, but it's nigh impossible to fish that river with a pole!  The locals use dipnets and fish wheels, but it's locals only. That river has almost no fishable side streams and the route is very steep sided hills - almost canyon like.  We floated from Chitina to Cordova and took the ferry back to Valdez.  You just can't beat the views!  The BSA folks up there did an incredible job putting all the logistics together for us.  Good luck putting this one together.