Not familiar with any campgrounds in Vista. One review on Google called Olive Park a trailer park.
You don't say when nor how long. But, I would suggest staying in Oceanside if you like to be near the beach and Paradise By The Sea is my choice. Oceanside is a short drive to Vista.
Or, you can go inland and stay in Escondido. There are a couple of nice RV parks in Escondido.
Wayne Lee
Out West Somewhere
2016 Forest River Sunseeker 3050DS Class C | Hummer H3 dinghy