Rent a modest car from the airport for the week and drive to Galveston. We stayed at a B&B called Avenue O B&B. Great place!!! AND you get a 5 star breakfast the morning of your cruise, you get to park your car at their residence (in the back area) FOR FREE and, they shuttle you to the cruise port for free as well and pick you up when the cruise is over and take you to your car at their place. They are about 5 minutes from the cruise port and is super fast to get there. (They are also cruisers...)