We plan on doing about the same trip next month we are in Riverside, not sure which way is quicker for you,to go up the 5 or over to the 15 ?
We are going up the 15 to the 395 up to Kramer junction hang a left at the 58, over through Tehachapi, spend the night at some little lake campground " Brite Lake" up there,
Then down the 58 through Bakersfield up the 99, you can hang a left at Visala go over through Coalinga or a little further up through Los Banos I remember a little camp ground there by a fruit stand. Pretty neat up there.
We are going to stay at Fleming Meadows campground maybe on our trip, we are going for about 2 weeks.
Up and then like you come down for the view, and stuff
hope you have a great time, and us too.