Just got back from 8 day trip down the Dirty Devil - it is a real awesome float but we got our asses kicked by two big storms - very high winds and blowing sand. I think you would want a level above 100 cfs, we put in at 125 cfs and ended up out of our packrafts a bunch the 1st day & half. Looks like the river went up to 425 cfs while we were on it. Cows above Robbers Roost Canyon, then no cows below - after Robbers Roost no more dragging boats. No Mans Canyon is way cool and we found lots of water about 1 mile up it. The narrows in Happy Canyon are world class - must do half day hike there. We floated 75 miles and took out just past the highway bridge, and hauled the packrafts up to the picnic area near the highway - the place we took out was bad - felt like Indiana Jones what with quick sand to mid thigh and tumble weeds up to my neck. Better place to take out would be at mile 66, a road goes up the DD about 4 miles (need high clearance vehicle) and this is right above a Class III rapid that has formed (at least when we were there) as the DD cut through the old lake bed since lake mead is down so far. We ran our own shuttle, only took 2 hrs round trip.
Over & Out,