Man, you're leaving it wide open...
If you're willing to drive, consider the Blue Mountains. There's a really good reason that Cycle Oregon seems to be there every third year or thereabouts. Look at a map of Joseph and the surrounding area.
Staying closer in, you could do something around The Dalles, including the Mosier tunnel, Rowena Crest, and the Columbia River Scenic Highway...
ORS 811.065 (1)(a)
The driver of a motor vehicle may only pass a person operating a bicycle by driving to the left of the bicycle at a safe distance and returning to the lane of travel once the motor vehicle is safely clear of the overtaken bicycle. For the purposes of this paragraph, a “safe distance” means a distance that is sufficient to prevent contact with the person operating the bicycle if the person were to fall into the driver’s lane of traffic....
LCI #2105 Lambchop Rides!