Train's not great - you can get to it from the SAN ramp pretty easily (across the street) but it drops you off at 'LAX' terminal which is about 30 minutes by car to the airport or you can take a few trains. There is regular express surface service from the train station to the LAX airport. You can also hire a towncar for about $265 one way or rent a car for about $40 one way (which you can't get reimbursed though).