I always go in the day before and last two times I got Holiday Inn Superdome for $99 (including cruise parking) and they shuttle us on the hour to several spots. ... including to the terminal the morning of the cruise.
personally I dont think you have time to park at the terminal the day of the cruise (the lines are horrendous early on and you cant go in and park early), and then getting all the way to cafe du mond and back ... and miss the lunch buffet on board??
Maybe Im missing something and you arent planning on doing this the day of the cruise ...but parking there a day earlier?? It doesnt sound to me like it would work the day of the cruise. .. except you mention parking at the terminal. ... this is not a easy place to drive into and park early the morning of your cruise.