Hwy 224 east of Estacada is a nice ride.
You can take that to Ripplebrook ranger station, then turn south at the junction. Goes all the way to Detroit Lake. Take Santiam Hwy back toward Salem, peel off on your favorite backroad and head north instead of slabbing it up I-5 (going up through Silverton and coming in the back way to Oregon City is nice).
Another ride in WA:
SR-14 to the Cook-Underwood Rd turnoff, take the Cook-Underwood loop (which returns you to SR-14 near White Salmon). Continue out SR-14 to Centerville Hwy (Lyle, WA). Enjoy the twisties on Centerville Hwy, then continue through windmill country to Hwy 97, turn south, take 97 back down toward the Columbia River. Then peel off on SR-14 and return through Maryhill, Dallesport, Lyle, Bingen, etc on your way home.
I'll leave the Cougar Run description for krolik.