I can't speak to either Young's river nor the Lewis and Clark, I have been hearing of success fishing spinners on the Columbia side of the Clatsop spit on the incoming tide. Since your going to Fort Stevens it's a short drive out to the spit. Bring your waders and #5 or #6 spinners in red / pink with nickel blades.
As well the Necanium has fish showing up as I write this. A buddy of mine just returned yesterday and his 8 yr old son managed to boat a 25 lb fall Chinook (with a little help on the hook set by dad of course)