Neil,
I am a Coug and had fish the Grand Ronde for Steelhead alot when I was there from 94-98.
This is a perfect time until freezing.

The steelies from this region are small around 3 to 12 lbs.
You will be amazed that the majority of them are chromers.

The mouth of the Grande Ronde and Snake in this region is your best bet.

To get to the mouth of the Grande Ronde from Pullman:
1. South 195
2. South 95
3. West 128
4. South 129 through Lewiston/Clarkston
5. South Snake River Rd (gravel).
Stay on Snake River Rd until you reach the mouth of the Grande Ronde.

Drift bait (eggs or small pieces of prawns) and cheap 99 cent WalMart Steelhead spoons (Chrome body with red) was the best rig I found.

In around March you should go to the Cotton Wood hatchery. This is where most of them will end up.
To get there, Stay on 129 and go through Anatone and down the Rattlesnake Grade.
When you hit the Grande Ronde, swing a left on the Grand Ronde Rd. to Cottonwood creek.

Same setup here.
But most of the fish are very colorful.
The locals here keep everything. They have no choice.

Another spot closer to campus is directly 100 ft above the Lower Granite Dam on the Snake.
The guys here use red coon shrimp on a jig under a weighted bobber.
Here you will have a chance to catch the bigger Clear Water Steelies which are much bigger in the 10-20.
Or you can use power bait under a float to catch smolt all day long.

Small mouth bass and channel cats can be caught below the dam in Almota or above the dam in Wawawai in the spring time.

Good Luck and have fun.
Oh, please verify my directions.
It has been a long time and my memories are shaddy.