I would focus more on the lower section of the river, or perhaps go higher if the river level is high. As you probably have heard already, there are many pullouts along the highway which frequently runs right next to the river, so you can hit those spots. Besides doing the search here, you can also either buy or borrow (from the library) "Fishing in Oregon" book which gives you a crude map of the river and a couple of dozen spots. There has been several Wilson or coastal river posts here in the last couple of weeks, so you should get some decent returns.
Welcome aboard