We took a boat tour of the area and also visited Mel Fisher's Museum. He is the person who has found gold and treasures in sunken ships. They also had a nature area across the street for walking. In the evenings, they had stories around a fire pit and maybe s'mores. They had some other activities at the resort, but I do not remember what they were.
If the manatees are there at this time of year, you can go on a boat ride to see them.