Did it July 7 to 14 of 2007. Water was fairly low - fishing was rediculous when you were away from popular areas and nearly non existant at popular camps. It was was actually crowded for a 20+ mile stretch starting just above the Big Praire ranger station. I'd suggest blowing through that area ASAP, it's much less crowded above and below. There were litterally hundreds of people in that stretch; 3 or 4 outfitted trips, lots of backpackers and several other floating trips. It was like a weekend on the Yellowstone!
Flows were just above 1000 cfs (gauge is way down by the lake), normal for the period was about 3000.... so it was LOW. We were probably floating (most of the time) on about 100 on youngs creek, then maybe 500 or so below the confluence. We only portgaged 2 log jams, but were stuck a lot, especially up in and just above the canyon on youngs.
We went in at Dunham pass I believe, Packed in with the Cheff ranch crew. We hiked in starting a day ahead of the mules. Met them about 15 miles in at the confluence of Babcock creek and Youngs Creek (southern trib that forms the SF proper, the other is Danaher). The creek was low and there is a canyon in it that was BONY. Essentially it took us 3 days to go 15 miles to the SF. We had planned on starting from a few miles above the confluence originally but we had a sedentary Seattlite that failed to train for back to back dozen mile hikes, so the packer cought us and we decided to put in higher. It was a fortuitous decision, as that was all of our favorite parts of the trip, even though it was A LOT of work. The main river was nice, but we had that stretch to our selves and it was just sooo beautiful and peaceful.
The narrows of the youngs canyon
We had a 13' hyside and a 10' mini cat, 4 people and 2 dogs. We ran 3 people and the dogs on the raft and one person and a little gear on the cat. We packed fairly light but did bring some beer and good food along with quite a bit of dried food and such. I believe we went in with 6 mules and used 4 to get out, maybe 3.
We saw no bears, nor any sign but were prepared with spray, shootin' irons and we hung all of our food related stuff every night. That included a kitchen box, 100 qt cooler, 3 - 5 gallon buckets and the river table/front bench. We had a blast setting up the highline to get that managerie into the trees.
We cought lots of cutthroat, but only 2 big bull trout... this one got the wife her first (and only) published photo...
I don't recall any bug issues... vaguely on the hike in, but I recall nothing once on the river.
Definitely an awesome trip. I can't wait for the kids to get a little older so we can do it again!
I will say one thing... I booked the packer 6 months in advance, and that was 10 years ago. I recall running into several that were already booked that far in advance. You may be SOL trying to get in there this year...I'd get on the phone ASAP and hope.