101 From Seattle to San Diego

I see a flaw in your plan, the 101 doesn't go all the way to San Diego. South of Santa Barbara, around Oxnard it turns inland and turns into the 210 which goes east & west across the top of the LA area. You can turn onto Hwy 1 (Pacific Coast Highway) in Oxnard and follow it down to Orange County or you can find the 405 and follow it down to Orange County. PCH has many slowdowns and lights. In San Juan Capistrano Hwy 1 ends and you end up on I 5 to San Diego.
We have been on the 101 through Oregon, very nice views but slow, you go through every little town and Oregon state parks are nice.