Take the Puyallup exit off I-5. This will put you onto River rd. Stay on it for a couple miles and eventually you will see a bunch of soccer fields on your right hand side. You will see a butt load of other cars parked along the road there. Join them. Guys will be all over the river here.
I don't know if there is an impact on the fishing or not, but the indians are netting on the lower river on sundays. To be safe, I would try on saturday. Have fun.