Was a rookie last year myself looking for info also. Lower river, from I-5 bridge down is now open (someone please correct me if I am wrong). Last year I started fishing in Mid march around Cathlemet (there is a great launching facility and marina there). I think the run should be at full strength around mid-april. I believe the season closes around May 7. Go to WDFG web site for the set seasons.
Had my best luck trolling during the outgoing tide with a 2 to 3 oz lead about 30 inches down on a spreader bar. Used cut plug herring and varied the offering with mid sized willow blade spoons and Hilldebrandts about 10'' in front of the cut plug. We used herring of all sizes jigged out of Grays Harbor and frozen at home. They were not pretty, but worked great in all sizes.
If trolling was slow or I was lazy, we'd anchor up and plunk K-14 quickfish in silver and chartreaus with a herring wrap. Used 1oz weights off the same dropper length. Took the front hook off and lengthend the back hook by putting on a barrel swivel and a split ring.
I'm a novice at springer fishing, but you should find plenty ofopportunities from Cathelamet to Longview. You'll learn lots just by giving it a go the first year. Lets hope for clear water.
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Chasing old rags 500 miles from home.