I just discovered that there is a new Cars and Coffee event in San Diego county, about 8 years after the Balboa Park event died, and it's in Rancho Santa Fe. Thanks Marc B!

Bring A Trailer says that this was kept to locals knowing about it until recently "a strictly word of mouth, invite-only kind of thing" but now it's an open to all event.

I can tell you a little about RSF, it's the home of some of the richest people in So Cal... ambassadors, bank owners, shiek's sons, etc, and there are some ultra rare and expensive collector cars that are in the garages and collections there.

11 years ago I was there checking out the gas station, which only needs to cater to the locals, and it had the right of grades of gas  https://justacarguy.blogspot.com/2008/05/unique-gas-station-is-pumping-100.html though it's around $5 for the cheap, 10 for the 100 octane, per gal.

https://bringatrailer.com/2019/03/22/bat-event-coverage-cars-coffee-rancho-santa-fe/
https://www.facebook.com/rsfcandc/