There is not a real train connection, but there is a free bus (line G) to the metro station Aviation, this station is on the green line of the Los Angeles Metro.
Car and bus
The airport is along the Pacific Coast Highway (Highway 1) and Highway 42, by the intersection of Freeways 405 and 105. Be advised: Highway 1 is called Lincoln Boulevard north of the airport and Sepulveda Boulevard south of the airport. From Los Angeles you follow Freeway 405 South and then the exit to Highway 42 or Freeway 105 West. The route to the airport is clearly indicated. During rush hour the roads around the airport are crowded.
The shuttle bus LAX FlyAway maintains a connection two times per hour between Union Station in the center of Los Angeles and the various terminals at the airport. The Metropolitan Express also goes to Union Station. For Disneyland you choose the Airport Bus that goes to Anaheim and Buena Park. From parking area C buses from the regular public transportation leave to several destinations in and around Los Angeles.
Car rental - Los Angeles International Airport
More than 40 companies rent cars at LA Airport, but their offices are not established in the terminal. You can call these companies through a special telephone by the baggage bands in all Arrival Halls. You can also reserve a rental car in advance using the service EasyTerra provides, they compare the rates of several providers in a single quote.
Taxis are in front of the Arrival Halls of all terminals. They have meters but for a few popular destinations there are fixed prices.
There are parking places a short distance from all terminals, that have, in total places for more than 8,000 cars. Two areas are a bit further away (Lot B and Lot C), these have lower rates, and the first two hours you can park for free. There is a shuttle bus to and from these areas (respectively, Shuttle B and Shuttle C).