There's a KOA camp not too far from the city that has tent sites available. I don't have a directory but you can find them online. Other options in nearby Orange County (Black Bear, for example) have RV sites, but none for tents. As you might expect, costs are a little higher than other places -- after all, it's the City!

I've never been to any of these, just found them for you with a little bit of searching.

Welcome to the RoadTrip America Forum!
Bob