Lots of good advice and the suggested route is excellent. If you don't mind the cost, you might consider getting the "Mad Maps" set for California. The maps list suggested routes with descriptions, plus lots of other info. Good for a first trip, and good for both the bike and RV segments of your trip
Definitely do the coast highway from Monterey south.
'02 BMW R 1150 GS-A, '07 BMW G650 X-Challenge, '08 BMW G650 X-Country, '09 BMW G650 X-Country, '03 KLR 650, '04 KTM 400 EXC, '02 Kawi KDX220