Southern california has probably the most diverse locations in the world.
You can go from beach to mountains, desert to urban and easily do it in a few days.
Also the most amount of municipalities (88) and covers close to 5,000 square miles, each with their own permit and insurance regulations.
Santa Monica, LA, Culver City, West Hollywood all are different with different rules and California like most states is very money hungry so . . .
If it's just you a model and a camera you can probably get away without a permit, but be prepared to be stopped.
Start with
http://www.filmla.com/ and go from there.
Also this has been a very cool summer along the coast with high temperatures in the Desert which means a lot of marine layer so plan accordingly.
The weather is finally breaking and now we're into the pretty light season.
If you want to work the desert, Death Valley and the high desert is about 3.5 hours drive from the West Side of LA and also requires permits for most areas.
The Desert is a really extreme area, either hot or cold or both, with amazing wind, or dead calm, sometimes all in one day, but really amazing.
If you want to work the desert for a full day, probably spend the evening in Apple Valley and start early.
If your going to work anything urban, learn the permit rules, scout the area early, especially where to park and don't expect just to drive over to Melrose, double park, unload the truck and start shooting without planning.
There are also over 2,000 talent agents in LA, some good, some great, some marginal, but finding good on camera talent will depend on the equity you have with the agents and the industry.
Don't take this as it can't be done, because there are multiple projects happening in every area, every day, from one person hand held to 4 grip trucks production, but it's not Miami where your working one beach, or NY where your only covering a few square miles.
Also don't let the size of LA bother you because if you do your homework you'll come away with some inspiring imagery.
BC