I would also recommend that you definately use either a ship excursion or a licensed tour operator. Gilley has a kiosk "inside the fence" and does local tours to the zoo etc.
However, if you are going a long distance from the port, I would recommend a ship excursion only.
Gilley and other tour operators are working really hard to get Belize to be like another Cozumel. They have the advantage in that English is the spoken lanuage there. However, it will take time for the people to learn how to be "tourist" friendly....and having folks come across the border from other countries (stirring up trouble) does not help.
You can email him for price and information at
His name is Gilbert Young. He is an older man with a vast knowledge and love of his country.
Have a great cruise!!!