It is now possible to book RCCI for the day before now. Stay at local hotels near airport and coutesy bus back to terminal C united bag claim between 930a and 10a.
Boarding time for Enchantment and Liberty in Galveston is usually 1100-1115.. Everyone has to debark off ship before loading begins.. Cabins are usually available 100p to 115p.
Giados is nice. Right across from beach, Eat at restaurant. Very good. RCCI has transportation from and to both airports. Around $30.00 per person. 40 minutes from HOBBY airport and 90 minutes from IAH.