I have not had good luck in Desolation in the mid-summer. Too crowded and too many others trying to do the same thing. I go up to the Broughtons, normally crab in 40 feet more or less and try to look for an outfall coming down from the land, a small drainage or the like. I have tried cat food, chicken and salmon heads for bait. Salmon heads seem to work better. Be sure your licenses are in order.
As an aside, you can't get to the Broughtons from the south without traversing rapids. But they are a non-event at slack water, so read the tide chart and proceed.
Best of luck, let us know how the trip went.