There are lots of Forest Service roads in the Rouge River/Siskiyou and Siuslaw National Forests in Oregon. If you want to do some dune driving then stop in Florence, OR and visit the Oregon Dunes National Recreation Area.
Read detailed trip reports, see photos and videos on my travel blog, luinil.com.
Visit my Patreon page: patreon.com/LarrieEasterly
Current van: 2002 Ford E350 extended body camper with Colorado Camper Van pop top and Agile Offroad 4WD conversion.