I cant speak for the Pullman area (go Cougs!) but Spokane has a great, free off-road park.
Theres a very cool 4x4 get together up north at a friends place in Ione, Wa. this weekend, but of course my Blazer is still in the one-ton conversion process. The irony is that the parts I'm waitng for to finish this project are at his place in
Ione! and wont be delivered untill after this weekend.