Back in August we actually took 299 out of Redding over to 101 and 101 up to Newport and 20 out of Newport over to I5 and up to Portland.
About 10 miles out of Redding I asked my wife what in the hell were we doing taking 299? But soon we hit our stride and it was one of the best trips we have ever taken. We pulled a 35 foot 5th wheel with our 2012 F250. They were doing some road construction to make the road a little wider and we really didn't run into any problems. You aren't going to find any gasoline stations unless you are in very small villages or towns. Or I should say you aren't going to find any diesel.
You will not regret this trip. Best of luck.