Thanks for the info.  Checked out the article, interesting. I have extremely light weight camp gear  -- as I've been an alpine climber for years. So I'm pretty sure I could fit all I need in a 20 liter dry bag for the 3-4 days down the Middle Fork.  Question is, what's it like to surf waves (the whole point of the trip) with a dry bag on one's back?  I'm going to test my gear here once I get some free time in a week.  Also, what grade water were you running when you did the 18 miler and where was it?  The Middle Fork can get pretty solid with a number of IV+'s with high water at the end of May.  I don't think I'm going to do it if it's forecast above 4,500 cfs.  Where are you based?  I'm in Missoula~Minot