Two things:
Thing 1: Buzz, I use an 8ft "Bronco" by Bucks Bag to cover the EF Lewis and Kalama. It is a bladder type catamaran, single seater boat. Sold my 16'x54" Willie (All my friends and relatives got their own drift-boats, so using a "bigger" boat is no prob.) I like inflatables for rocky areas and low water. They are more forgiving. I saw a small 10-14ft mini-drifter get pinned on "Oh [Bleeeeep!] Rock" below Heissen in Dec '96. Nothing hurt but pride, 'cept the boat was lost. My bro-in-law lost his green/white 16' Clackacraft Jan 12th this year on EF Lewis when his anchor bracket got stuck in a tree, fast water did the rest. Mark Angel got the boat out and it was repaired. 10ft boat, with experienced guy on the sticks, normal flows, would have no prob with anything below Daybreak (EF) or Red Barn (Kalama)
The "Bronco" comes in handy late in seasons for Moulton to Lucia to Heissen or Lewisville on the EF or Upper Hatchery to Red Barn on the Kalama, Mechantile Store drift on Washougal, or even the Coweeman River. I have had it on every Columbia Trib below Bonneville except the Grays and Cowlitz.
Thing 2: Flyfishing the EF, water below & above Daybreak, also above Lewisville. Possible canyon water for summer-runs above Moulton. Green Butt skunks always a fav. Check in with "Greased Line Shoppe" for more.
Extreme.