LGA is the one place where I enjoy having a lounge prior to a WN flight. The flight back home leaves in the middle of New York rush hour, so I commonly head out to the airport very early. In the Air Canada lounge I can work, grab food/drink, and generally minimize my time spent in the 3rd world bus depot that is the Southwest terminal at LGA.

AC is outside security. I think Centurion is too (?). Definitely usable on WN itins...short walk to the TSA checkpoint for WN.