Some of our favorite places up the coast are Pismo, Morro Bay and Avala Beach. Avila has first come, first serve spaces overlooking the bay. Although these are a half day drive from Ventura.
One place we stayed was Julia Phiefer ( sp ) State Park. It was off the 1 around Big Sir. They allowed overnight dry camping and it was beautiful.
There is plenty of beach camping north of Monterey in the Monterey Bay. Sea Cliff SB is our favorite and they do have a few spots a day on the lottery system.
Then head thru Watsonville, over Pacheco Pass, thru Los Banos to the 99. Your at the foot of Yosemite.