Stay in Santa Monica, and stay out of the rest of LA
Santa Monica is one of my favourite spots in the US - the beaches are beautiful, the boulevard is great, and the people are super lovely - but the rest of LA I wouldn't go near with a 10 foot clown pole. Hollywood was good to go to just to say you've been to Hollywood and tick it off the list, but I found it a let down, not least because it just feels so dirty, and I have no desire to ever go anywhere near it again.
Insider Tip:Go to Hollywood for a day, then just stay in Santa Monica. The rest of LA is not worth your time.