We have traveled quite a bit in Oregon... sort of depends on what time of year you are going to be traveling. Soon, if looking for fall colors and near water, the time is now and the next 2 weeks. All of the Oregon State Parks are nice. Always nice bathrooms, and many times full hookups, but sometimes only power and water. Check out the Oregon State parks website here: Oregon State Parks and Recreation: Visiting State Parks - Find A Park
Some campgrounds will close for the winter, so always check if they will be open.
Some beautiful places: Most sites on the Oregon Coast, Silver Falls State Park out of Salem is a real gem, beautiful water falls ~ especially nice in Spring. Out of Portland is Champoeg State Park along a river. The actual campsites aren't beautiful, but they are nice with full hookups. A lovely drive down the Columbia river is special along the gorge, beautiful trees and on the north side of the gorge a wonderful 2 lane old highway... I haven't stayed at Memaloose State Park but had friends say it was nice. It is close to the freeway, however.
I haven't stayed in Washington lately, but we always enjoy the Olympic National Forest.
Good luck! Have fun!