There are quite a few good areas in Washington, such as:
Naches area (also known as Shoestring, or Manastash ridge [and a area called Funny Rocks])
Rimrock area (south of Naches, but within an easy 45 minute drive, all highway, so street legal is nice), steep, long climbs, some severe off cambers. Potentially dangerous.
Elbe Hills ORV area, on the western side of the state, but fun. Got some muddy trails during the wetter seasons
Evans Creek ORV area, also on western side of the state, also fun. More terrain variations than Elbe, dryer, and more snow in the winter months. Both these are in the foothills of Mt Rainier, one on the northwestern slope, the other on the southern slopes.
Walker Valley ORV, further north, in the foothills of the Cascades, some fun trails, but rather limited in area.
Moses Lake sanddunes. Middle of the state. Relatively small dunes, but great fishing opportunities in bunches of little lakes.
Thanks again for showing me the trails in your neck of the woods 2 years ago. Unfortunately, I'm short on vacation time this year. Might try Digger5.