We take the route from Keizer to Lincoln city all the time. IMO it' way better than the route from I-5 thru Cornvalley/Philomath. That can get slow if you hit it at the wrong time. From Portland head south till you get to the 99E exit, follow that to Marion ST. Then turn right and head over the bridge. When you hit Marion St you are at the bridge. Going this was is way, way easier than the 22/Mission route.
I've done both and both take the same time. 34 will put you in Newport. Only draw back it that you still have to go thru Lincoln City to get to Newport. During the week or day time it's not so bad. Around 5:00 on Friday night it sucks.
Even when we stay at South Beach St park we still go thru Lincoln City.