I dredged the Crazy 8 claims I think 4 years ago, and from my experience, I wouldn't bother. If memory serves (and nothing has been changed) they were all on Lake Creek except for maybe 1 tiny piece on Douglas, and there was much less gold on it, all fly speck size. I remember that wherever I tried, I got down a couple feet and found an old flume at the bottom of the creek and couldn't go any further due to the solid flume bottom so I'm not sure it's even the original creek bed. Might do ok if you can find some untouched ground I guess or get around that buried flume. I'm not sure if the entire creek has that flume buried or not, I only tried 2 places.
I think you'd do better on Douglas creek sluicing if you can find bedrock and someplace that hasn't been dredged before (which is getting pretty hard on the GPAA claims at least). Bedrock is about 3ft down, reachable by shovel if you have time and patience, or find an old unused dredge hole. Most of the gold is right around bedrock.
There used to be a WGS excel spreadsheet online that had every single mine, prospect pit and placer in WY, along with mineralization and lat/lon and deposit type (polymetallic vein, massive sulfide, pegmatite, whatever). All I can say is if you can find that thing online still then you'll do yourself a huge favor and have weeks worth of research fodder, but I think they removed it.