I agree with the time savings of parking at the port. However, for Galveston, there are parking lots that are not terminal run that offer less expensive parking and are at most 100 ft of extra walking compared to the terminal lots. AND some of the terminal lots (the less expensive ones) are shuttled anyway so you don't save any time using them.
SO I guess what I am saying is that not ALL ports have more convenient parking.
Carnival Cruise Lines:
Fantasy 90, Celebration 95, Victory 05, Conquest 05, Spirit 6/06, Freedom 6/08, Holiday 7/08, Victory 6/09, Valor 9/09, Dream 6/10, Splendor 8/10,Conquest 8/11,Magic 11/11,Triumph 4/12,Spirit 7/12,Freedom 11/12, Triumph 2/13 - The fire cruise
NCL Dream October 2006, RCCL Mariner OTS June 2007