This small museum is open Tues. through Saturdays, 9 a.m.-4 p.m. In September, and some other months in the slow season of Florida, the gift shop closes at 3 p.m. I missed it. There is a box for donations. No cost is required for entrance.
Right now, until 9/28, the museum is featuring photos of the everglades taken by a local photographer. They're mostly pics of birds. For me that was the best part of the museum's exhibits.
The lady at the entrance desk, probably a volunteer, started us on our self tour through the museum, talked a bit about its history and the Marco "cat", an item which was found in an archaeological dig and is now at the Smithsonian in Washington, D.C. This museum has a replica of the cat and a very large replica of it outside on the grounds, which are quite attractive.
I learned a little more about Marco Island that afternoon. It was a good experience.