It's fairly expensive to get from the airport to the city via train (especially with 2 adults and 2 kids) and usually works out about the same price to get a taxi. You can then jump on a train to the GC. Otherwise, just hire and car or jump on the shuttle straight from the airport and be done with it all . That's what I personally would do... nothing worse than lugging 2 kids and luggage on and off multiple trains etc etc.