The Crooked River is special and worth a visit and good fishing day. We are below normal winter flow for some reason, so I think it will bump from 72 cfs to about 100 cfs and hold there for the winter. 72 is fine, 100 just gives the fish more habitat. 
PMD’s are still going and mixing in to the BWO’s that we think of as the Autumn time hatch. 
The Furminky’s BDE Dun is a good fly to transcend both hatches I believe. It is one I reach for when I fish the Crooked in the fall. 
Nymphing is great, but with lower water lighten your bead and probably go to one singe fly to minimize weed snags. I also prefer to fish a NZ Wool indicator over euro style in lower water as it allows me to be more flexible in putting the fly in more water types and areas. 
I still have some, but not sure these are available any more but Tiemco (the Japanese hook brand) used to make these hot pink sticky foam rectangular strike indicators. I would cut them in half and space them 5 inches apart to see 2 indicators that were both very small work as a team. Why 2? Two would line up and in the seam telling you if the drift was correct. Two would be easy to watch and you often see the subtle “slide” happen easier than with just one. My next trip to the Crooked I’ll pull them out and use it again and report if it’s as hot as I remember. I’ll also check my Tiemco distributor and see if they have them still.