The galveston Holiday Inn also allows this. And provides a shuttle. But if you are traveling March 18th, you may be out of luck on a Galveston hotel room reservation. If you are forced to find a room in huston, look into reserving a parking spot at EZcruise.com They offer port parking at a reduced rate and offer the same shuttle services to the ship as the cruise parking does.
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