This is sort of a trip report, but I want to contribute on how you can can get around in LA.
I am here in LA on a trip, but I found a free day to explore. I always wanted to get as much metro "rail" in, in a day, so that's what I did (and putting in an Amtrak segment along the way). Notice that I've quoted "rail" because silver and orange lines ain't rail. I'm staying near LAX (the airport), so my "home" station is green line LAX station. Here it goes
Leg 1 - Green Line
Green line from LAX to Harbor Freeway station. To transfer to Silver line.
Leg 2- Silver Line
Silver line is a bus (like Boston, come to think of it). It's fast when no traffic, but costs more than usual rail fare, and not too comfortable (and cannot really have luggage as this is basically a city bus). I wanted to transfer to Red line. I had an option of transferring at the 7th St Metro Center or Union Station. I opted for the 7th St. Transfer was super easy (the Metro Center station right at the Silver bus stop).
Leg 3 - Red Line
Boarded at the 7th. Went all the way to North Hollywood. Intended to transfer to Orange line. Again, the transfer at North Hollywood was super easy. Many people on the train, most got off at Hollywood stops and Universal Studio (tourist-y places).
Leg 4 - Orange Line
Another bus. Wanted to go to Chatsworth. Bus lane all the way, so no traffic. Wondered why they didn't convert it to light rail, or trolley. Train ride is so much better.
Leg 5 - Amtrak Pac Surf Liner
Now an Amtrak! I actually was ticketed for later time the same day, but the conductor accepted it without a blink of an eye. So if I can contribute anything, here it goes: yes, you can buy an unreserved ticket for a later time and use it on an earlier train the same day. Got off at LAX (union station).
Leg 6 - Red/Purple Line
On the way back, I wanted to go with a different route. Specifically Blue to Green transfer. But to do so, you must first take the Red line or the bus to 7th St Metro Center. So I just hopped on the first train to the 7th St.
Leg 7 - Blue Line
Boarded at the 7th St. Went to Willowbrook station to transfer to Green line. The rumors are true that people are always trying to sell you stuff . It's actually not too bad, but it does have a bad rep.
Leg 8 - Green Line
Willowbrook to LAX. Final leg.
There you have it. The cost: $13.50 AAA Amtrak fare CWT-LAX, plus just $5 Metro day pass. That's it!! Could have been lower if I wanted to take Metro bus/rail instead of Amtrak, or just take the Metrolink, but I wanted to get some rail points for my trouble (and cash in on Double Days).
Of course, during my stop at the Union Station, I went to Philippe.
Another place you can get to with Metro Rail: Langer's Deli. Red line to MacArthur Park. Not the greatest neighborhood, but I like the food. Some called it better than even NY delis (them's a fighting words, I know).
Also, you can hit all of Chinatown, Little Tokyo and Koreatown, all within the reach of Metro Rail. Chinatown (old original one) is practically next to Union Station. Little Tokyo is one stop away from LAUPT (red/purple line). Koreatown is along the Purple line (any stop with "Wilshire" on its name). Some of the most excellent foods in all locations!
Oh, I guess I could have also used LAX Flyaway as above poster mentioned, but then where the fun?