Complex sentence: With the exception of Terminal 4, all AirTrain stations are outside the terminal buildings and sit on the other side of the terminal roadway from each building and are connected to their respective stations through elevated walkways over the roadway.
Split into simpler sentences: With the exception of the Terminal 4 stop, all AirTrain terminal stations are outside the terminal buildings and sit on the other side of the terminal roadway from each building. Most terminals are connected to their respective stations through elevated walkways over the roadway.