There already is a Treasure Island casino. It's in Las Vegas and tacky as all get-out. The theme park may be small, with a theme of high technology. Or the theme park could be on California, incorporating the museum of artifacts from naval history and the Golden Gate International Exposition, the theme park that occupied the island from 1939 to 1940. That's a word with resonance.
Nobody can say an exposition is an inappropriate usage for Treasure Island.