The worst part of the drive is Tillamook. There is construction in the downtown area where they are preparing for a new, easier transition for northbound traffic from the one-way streets of Tillamook to US-101 north of the city.
Headed southbound you shouldn't have any problems.
Lincoln City can be very heavy with traffic and delays. We used East Devil's Lake Road to bypass that a couple times in July.
Recommend you start in Astoria. Visit the Maritime Museum, take the water front trolley, walk across the street to the Bow Picker for great fish and chips, Lewis and Clark Fort and the Column. Ft Stevens is a great CG. Each and every one of these is a great experience.