We live a little south of Portland. For quick weekend getaways we like to explore the Mt. Hood National Forest. The last couple years Elk Lake (North of Detroit > NF-46 > NF-4697) has been a huge draw. Signs to the lake say 4-wheel and high clearance only, but not a real technical trail, bumpy road but still fun, you gain tons of elevation.
But I am a Central Oregon kid at heart, and this past year we did Little Cultus to Irish/Taylor Lake to Waldo Lake (West of Highway 97 North of Highway 58). Road from Little Cultus to Irish/Taylor Lakes is a narrow dirt track, winding through the trees. The Lakes are a resting point for some people that hike the PCT. From Irish/Taylor Lake to Waldo Lake the road gets technical in some areas, mostly in a recently burned out area (down trees, rocks, tight spaces), but a huge confidence booster.
If I had the time I would spend it in the Eastern part of the state, too many places to list in the Wallowa, Umitilla, and Ochoco National forest.