based on chorter's experience & also that of another friend who suffered on the tanner trail (desert view), we opted out of this trip when we were in AZ last week.
budget 2-3 days of paddling, mostly flatwater, in a stunningly beautiful desert canyon ... then a FULL day, & then some, for the hike out (8-12 hrs with boat & gear).
chorter sez 3,000 - 4,000 cfs would make it more tolerable & quicker. know before you go that the water is NOT filterable (too much silt & minerals). you have to carry it with you (that's a lot of water). chorter's group ran out of water & got lucky by running into a nice rafting group on the grand that hooked them up prior to the 10 hr walk up & out. couldn't imagine doing that walk w/o water.