In the details, you lease the island from the town, and you also pay out of your own pocket in order to maintain the island (except for certain emergencies involving a few facilities such as “the toilet block” and “the jetty”).
You are expected to hire necessary staff and operate the public amenities, and to have prior experience as such an operator (ie you also own a pub somewhere else).
Power (energy) is required to be “GREEN.” And, that has yet to be established.
No mention of How to Repel Boarders (your duty to defend).
You do get to say when and what is open; but, there is an expectation by the town, that you will attend to the work. What the island has to offer, is seasonal - sounds like summer months.
I would guess you charge enough to cover expenses.