Most all of the trails in the Hood River County forest are multi use trails unless specified otherwise.
Meaning if the trails are open to moto's they are open to everyone and if the trails are non moto they are open only to non moto.
None of the trails are mt. bike only and at this time there are no "downhill" only trails.
I am a Mt. Biker/Runner/Equestrian and frequent the trails. I have encountered several mt. bikers from Portland this summer that did not know our trails are multi use and multi directional.