I'll try to be brief here, but wanted to get some info out there about the SF, as there are few people that have floated the length of this jewel.
After hiking 24 miles from Lodgepole to the confluence of the Danahar and Young's Creek in one day, the five of us laid over near Big Prarie--mules brought in our 13 ft. NRS Otter raft, two kayaks, and our supplies.
For the most part, the SF is class I-II. Once you pass the white R. confluence there are a few low-end class IIIs that keep you alert, as well as the occasional hole and wave for surf and play. The fishing is absolutely incredible---I caught 19 Cutthroats in the span of 15 minutes out of the same hole...needless to say we ate plenty of fresh fish. And the scenery is wonderful as well. I have paddled in Chile and Argentina and the water is as clear on the SF as it was down there---you could see the bottom of 25-30 ft. pools.
Mid-Creek is the typical take-out for rafters. By the time you reach this point the river begins to change dramatically. Over the next three miles or so there are very narrow slots (3-4 ft.) that required brutal portages for the raft and gear. Solid class IV water with small drops and narrow chutes requiring technical turns. Scouting is a real pain in most cases and nearly impossible once you are in the Meadow Creek Gorge. Right below the pack bridge at Meadow Creek there is a nasty undercut that swallows the whole right side of the river.
We had two close calls with the raft getting into small, hard to catch eddies above narrow slots too small for the raft---if we hadn't of set two people on the shore waiting to catch ropes, I believe our raft would still be in one of those slots.
We were told "Hell, nobody takes a raft through the gorge", by one of the packers taking folks out at Mid Creek, but figured we would give it a go anyways. It was a lot of work getting through, but as I look back now, I'm glad we did it, what a great experience---however, wouldn't take a raft through it again. We took seven days to make it through, but with kayaks only, partly self supporting, and in part having goods dropped at one of two spots, it could easily be done in 3-4 days, with maybe one portage.
If you have any questions about this run feel free to drop me a line.