We used I-10 to southern Arizona, then I-17 at Phoenix north to I-40. Get off I-40 at US 395 and take that north, stopping at Yosemite. 120 west out of Yosemite to I-5. Then north on I-5. You probably want to go west again from the Sacramento area to connect with the 101. I refuse to drive an RV thru the Bay area myself so we aim for north of that area to connect with 101.
By doing this you do miss the Big Sur area but the coast of Oregon and northern California are just as scenic. Once you get to Oregon you will have to turn of the 101 to get to where you are going.