I recommend lunching in Cambria, as it has far better restaurant choices than Pismo Beach.... although Splash Cafe on Pomeroy in downtown Pismo is world famous for it's clam chowder.
In Cambria, Moonstone Bar & Grill on Moonstone Beach Drive offers excellent food with a gorgeous view. Ask for patio seating to take full advantage.
Robin's on Burton Drive is another fine lunch choice or the Main Street Grill, if you want something faster.
On your drive down from San Simeon you'll pass through the beach towns of Cayucos and Morro Bay. Morro Bay has a nice embarcadero with shops, etc. to enjoy.
Once you're on the 101 heading south, take care as you crest the hill above Avila Beach Drive. You'll be treated to an awesome view of the ocean, but accidents are common here because people slow down too quickly because of it. So just stay focused on this part of the highway while driving. If it's a particularly clear day and you want to stop somewhere to enjoy the views, take the first off-ramp (Spyglass), make a right turn into the left lane. Turn left and continue to Vista Del Mar. Turn right and continue to Ocean Blvd. You'll see plenty of places to pull over with forever views.
From Pismo, it's mostly farmland until you exit from the Gaviota Pass into the Santa Barbara area.