...And I think I would take the Seven Devils Road. On a weekday you will probably see some logging trucks. They were cutting in that area the last time I was on Seven Devils. The possibility of a few trucks is better than the certainty of traffic on U.S. 101. Caveats: 101 has better shoulders, and fewer undulations. I have a problem with high noise, and would still pick Seven Devils. The city streets in Coos Bay are friendly-ish.
Another alteration I would do is in Lincoln City, OR. I would cut off U.S. 101 and go around Devils Lake on the east side. The traffic and lights on U.S. 101 seem endless through that area. The traffic can be aggressive with people trying to get around RV's from red light to red light. The east side is residential, and there are driveways, etc., but the speed limit is 25 for most of it, and the traffic is light. Here is the section
https://ridewithgps.com/routes/29658830
I would also opt for
Lost Coast Highway south of Eureka. If you're not averse to sections of gravel roads there are lots of
very scenic options to U.S. 101 between Eureka and Leggett that don't involve the portions of U.S. 101 that are freeway. The section of U.S. 101 in the Fortuna-Garberville area is quite underwhelming. West of U.S. 101 there are few paved alternatives, but more gravel alternatives. There are still hills, but they are more enjoyable than the U.S. 101 hills, and with better views. Most of the route I have linked here is paved. If you choose to try it, take food and water because there aren't many services out that way. The Leggett to Fort Brag section, while fun on a motorcycle, is full of tight corners and narrow lanes. Fortunately, it's relatively quiet, so you can hear traffic coming. There are a lot of blind corners, so be cautious. I don't think there are any alternatives to that, because of the rivers and terrain. The payoff at where Highway CA-1 reaches the coast north of Fort Bragg is a fantastic stretch of coastal beauty.