Make almost this same trip twice a year. Tucson to Phoenix, west on I-10 to Quartzite, north on 95 to Las Vegas. Continue north on 95 to Reno, then Hwy 395 towards Susanville. CA. You are in California for a very short period of time and distance and no traffic to speak of. Head north again just prior to Susanville and head towards Oregon on Hwy. 139. North from Klamath Falls, OR to central Washington or cut over to I-5 on Hwy. 58, or alternatives Hwy. 26, Hwy. 84 etc. All good roads and little or not traffic compared to the interstates, I-5 or I-15. These are not a turn by turn directions, but if you look at a map or mapping application you will get the idea.
Hope this helps.