Before the water cools below the 50 degree mark the walleye will be gorging on baitfish. Please note that typical bait fish this time of year run large due to the fact that they've been feeding all year. So what to catch them on....Jerk Baits and Shad Raps (Rapala). These are the fall go-to baits in Michigan and I can only assume it is in Oregon as well. When I say go big, I mean don't be afraid to run a 6" (size 11 I think) or larger Husky Jerk (rapala) in black and gold. Bigger is better they aren't wasting energy running down small bait fish, they're trying to get the most bang for their buck.
As to where to find them holding. In the river look for steep rock walls at depths from 10-40'. They trap bait against these walls and school them up here. Cast parallel with the wall and run the entire length of it. If you can tweak your diver to actually make contact with the rock, all the better. Run em fast and erratic. Other locations are: rocky points jutting out into the main current (run baits along the top and back side), any current break especially troughs running perpendicular with the flow of the river (a one foot trough can hold many fish), Grass beds in the 5-10' range hold fish. And of course with any fish on a feeding binge make casts where you'd least likely expect them. I've caught walleye in four feet of water in the middle of a sand flat.
My largest walleye in Mich came on a storm thunderstick in lime and chartreuse fishing in March with two feet of snow on the ground and the river running at a balmy 48 degrees. JERKBAITS are killer on cold water walleye.