Never even crossed my mind to do it that way but it sure is a good idea. Im sure it would be a lot of fun but you can always run into the bad like your raft going flat or tipping and losing all your equipment.
That river was also named the River of no return in 1984 so if that doesnt say something then im not sure what does.
I have hunted that area via foot at least 3 times, camping at one of the hot springs on the river (that's a different story). The big concerns my buddy (who has all of the rafting gear) and I had were that the water flow is often so low that you will be portaging in some spots, that the put in and take out are many hours apart and not easily feasible to figure out the transportation options short of paying someone to drive your vehicle to the takeout and the fire season. One season, there was a landslide that blocked the river and it was almost an act of congress for the FS to use dynamite to remove given that it was a Wilderness Area. I guess the number of stuck rafters finally got them to take some action. Also, we typically found the elk in September at the top of those drainages 1500-2000 feet above the river, so lots of climbing. There are enough creeks and water that they don't need to come to the river for it.
