a suggested quick visit to LA
If you are in LA only for a couple of days, here is my personal list of things to see and suggestions on how to get organized for that. You don't need a car
1st day: the city
start from Union Station, an old beautiful train station (reach it by bus or metro, by car you can find reasonably cheap parking). Have a walk to Olvera Street where the historical core of LA is (the old mexican market, the oldest house in LA, the mission of Our Lady of Angels, el Pueblo, it's all there - 2 hours). You can walk towards downtown switching between grand, hope, flower, spring street. Along the way, have a look at the downtown area (the skyscrapers, the city hall, Walt Disney Concert Hall - 2 hours), take the metro redline at 7th / Figueroa to hollywood/highland and visit Gruman Chinese and Kodak Theater, walk of fame, it's all there (2 hours). You can take here the Bus to LA zoo and from there the bus to the Griffith Observatory. You must book in advance by internet. Be there at sunset, when LA turns lazily into the City of Lights (you can stay there until 10 pm).
If you are not tired yet and want to spend the night out, do it at Sunset BLVD, in the suset strip. There are some clubs that have made the history of music/glamour like The Roxy, The Viper Room, Wiskey a gogo. Take a taxi back to your hotel if you are late.
2nd day: the beach
take bus number 20/21 downtown to Santa Monica. step out and rent a bike somewhere with a locker. you can ride the bike all the way to Venice beach, there is a very nice byke\\pedestrian path. Stop where you like and enjoy the beach, people watching, entartainers, shops, etc. You can spend all the day and early afternoon to go and come back.
At Santa Monica I suggest a walk on the mythical pier and along third street promenade. At sunset stay on Pacific Palisades park at Santa Monica, another set of an endless number of movies. Enjoy the sunset and twilight on the Pacific.