River maps publishes an awesome guide for deso. RiverMaps Map Books
Camping tends to be ideal, with cotton wood shaded camps that have sandy beaches in front of them at low water. I've layed over at 3 canyon before, but i think you could find plenty of nice layover camps in deso.
Rock creek is considered the most reliable water source, it should be filtered, you may not camp there, including down stream on right for a ways.
Last i heard, Ute permits are once again being sold, and the tribe is honoring said permits now.
You can double check with them, contact info on rec.gov.
Also should be aware that the road to sand wash is a VERY rough 4 wheel drive road that becomes a sand wash( god i love driving down that wash!) that would we a problem with rain.
Best money you ever spend is paying River Runner's out of vernal to run shuttle for you, they do a great job, and it will save you an 8 hour shuttle. 800-nine 30-7238