Try the upper reaches of the deschutes, above the impounded water. Smaller river, gorgeous country. It is a drive though.
You can also head much further east - most streams on the high desert side of the cascades are open year round. You're not going to find a lot of folks giving away their small water haunts very easily - simply put - those waters can't stand a lot of pressure. The instant you post something on the internet - it's not just a few people accessing it - it's out there for everyone. Sites like OFF, and iFish are a blessing and a curse for our fisheries, and fisherman. They let us spread news about political actions, ecological disasters, they let us share techniques and gear reviews... but at the same time, it only takes one person sharing a "hot bite!" story to ruin what had been a low key fishery. Sharing info on big waters like the Deschutes, the Columbia, the Willamette, the McKenzie, Wilson, etc is one thing. Sharing info about your neighborhood creek is another. There's some waters I fish that make me wish I had a Star Trek like cloaking device - because I'm sure people have seen me fishing, and catching fish - in places and then come back and pounded the same water.
I hate to say it, but sometimes you just have to get out and LOOK for yourself to find some of these places. I'm sure you did the same thing when you were in California, and you probably don't want to share all your high sierra honey holes with thousands of other fishermen.
There are streams I fish that I know get some pressure - but it's probably maybe one or two anglers a week, or a handful more. If I post up on here even a stream name, or a spot on said stream - there's always that possibility that the bite chasers are going to flock there, and you can go from a very small number of fisherman, to a hundred guys a week pounding that water. I've already witnessed an increase in stream side trash in some of these places, because other people have mentioned stream names on the internet. I admit - I'll make up a name, or flat out lie and say it was another stream sometimes just to throw the bite chasers off. Sometimes I just keep my mouth shut, even though we all have that urge to share and get attention for catching some nice fish.
I will say this - if you're from the Portland area, and you like catching fish on smallish water - wait until the end of may, then drive up Hwy 224 and follow the river above the lakes, and fish the upper reach of the Clackamas. There's rainbows, cutthroat, and a few brookies up there. It's a smaller water body - with stretches that look like the OP's picture. There's good camping up there too, and it's public enough that people aren't going to get uptight about one more person fishing it.
If you're located closer to Salem - fish the North and South Santiam rivers. Excellent trouting, beautiful scenery, not really big water. Again, it opens at the end of May.
If you are willing to drive - head over the mountains and try the Metolius, or the Crooked rivers.
Can't just have everything laid out on your plate for free.