it might take some looking, but search old posts and you'll find a link to the blm's guidebook for up there. it shows all the camps- some of them below twin bridges being kinda hard to spot.
if you're doing your own shuttle, i'd say 131-70 is your best bet. the river road's obviously shorter, but it gets kinda rough down there sometimes.
as far as time, remember it's like 55 miles. and pretty much flat after twin bridges, with a few small exceptions. 900cfs is enough to do it for sure, but for me i'd say 3 days might be a stretch.
All I need are some tasty waves, a cool buzz, and I'm fine. - Spicoli