There is not an RV park that isn't at least a two hour drive to Beverly Hills during "rush hour". The freeways - are "free flowing" (more or less) from 10 a.m. to 2 p.m. But there are no guarantees. The times "WoodGlue" quoted in his posts are NOT DURING RUSH HOUR.
I would stay at a hotel nearby if there is any way you could afford it.
I lived there 50 plus years and was an outside salesperson who drove these roads for 30 years until I retired.
The Bell/Florence area is not a place you want to be. There is a good chance Dockweiler and the Long Beach RV park will be full.