I just did the lower box this past Saturday. Flow was about 200cfs. It was a blast! 2 duckies and 4 kayaks.
Yellowbank we scouted and some portaged some ran it. Powerline Falls was unrunnable with tons of huge boulders blocking any entrance to the rapid, the water spews out from under these rocks so you could possibly run the lower half of it, but there no way to enter the rapid at that flow. Must portage it.
Pinball and the rest of the rock garden were really a blast and screaming right has a sieve of rocks at the bottom you can either boof off of or go left around them, I boofed off it to far right and got pitoned (sp?) im my duckie, which made all the kayakers go far left lol.
There was a red canoe wrapped in left side of Deadcar, why is it they never make it past Deadcar? lol.
The rangers and everyone else has gone home for the year, so you do get the whole place to yourself. We saw much wildlife as well.
I can only reccommend a couple things.
Get an early start and be prepared to paddle 18 miles non stop. Launch by 10am at the very latest. Set your shuttle by 8am. The low water makes for very little current through the pools, and even paddling the entire day, it still can take 8 hours. Add in a wrap or a nasty swim and the time that takes and it can be dark before you get off the water. I did pack a headlamp just in case but didnt need it as we got off the water around 6pm from a 10am launch with no on-river delays.
Be prepared to do a lot of rock hopping and boofing etc. Dress for creekboating and potentially cold weather. We had 66 deg F air and 46 deg F water.
Bring a wrap kit.
Bring a spare paddle.
Anyone coming down to paddle the box shoot me an email at firstname.lastname@example.org
Id be glad to come along if I can!