<p>The metro really isn’t any worse with luggage than the airport, really; as long as you haven’t packed more than you can carry you’re fine. The bus that goes between the airport and Union Station is realllly nice ($3 one way), and the metro stations have elevators so you don’t have to carry stuff up & down stairs. The walk between Caltech and the nearest station isn’t bad either. Altogether that takes about 2 hours, as korinfox said.</p>