If you get the Princess transfer you get the color luggage tags and let them bring your bags to the baggage area in the morning, just grab them on your way to the bus. Transfer drops folks off at each airline entrance. They need your flight information and will also tell you any custom info you need to know. I would think that would factor in you transfer time to make your flight early enough.
If you don't eat before you leave the ship do this before security at the airport, more choices, but somethings can't go through security so beware what is allowed.