I'm heading to Oregon in April with a buddy and we too plan on hitting Washington for a couple rides, so I hope someone chimes in on the best places. I've done some digging and it looks like Tahuya has some good riding.
The seasons really dictates the areas and conditions. My family really enjoys evans creek area, high forested mountains, steep accents and decent. But gets snowed in from dec- sometimes Memorial Day weekend. Elbe hills has large muddy tank traps, that can challenge and destroy the toughest of rigs. Tahuya is some what mild, and flat. Some decent man made rockcrawling if that’s what you are into. Natches and liberty have some pretty fast moving trails and beautiful sights to take in, but can hold onto their snow pack into late spring early summer depending on the spring weather we get. Walker valley has one pretty challenging 4c4 trails up in the north end. Definitely worth a day trip