So, I happen to be from Los Angeles. It actually is possible to get around by public transportation, but there's good reason people say it sucks. It's ridiculously inefficient. It's not its fault really, it's just that LA is a huge, sprawling city. So it can be done, but it's time-consuming as all hell. Driving is generally easier.

I can give you a better idea, if you'd like. Just tell me where they live (as in the town name) and where you were looking to go. I know my way around.