How do you feel about development of the site? Is it worth the time and money? Do you think a well developed site will increase the value enough to actually make it worth the effort? Thanks for the responses.
At minimum, I'd build a quick one-page lander for it, with a few photos and short descrip of the area and, if you're selling, some points why this would be a great domain to buy - for an example see my OkanaganLake . com, I do this for all my geos.
If you want a little more dev, contact every business you can find that is on the island, ask them for a photo or two and a quick write-up and tell them you'll give them a free page on your site. This works often, plus you mention it's 'just until you sell the domain name' and that also lets them know it's for sale.
* It's always nice to find an end user who has your exact domain within their domain name, for example SouthBiminiRentals.com is someone to approach

Even if they don't buy the name, it's a free way for you to get some content to build out your site, and it's free advertising for them.
To sum, I'd do just a little dev at this point, not spend hours and days on it; it's a forward-looking name especially if tourism is growing there. Right now things look slow, very few businesses on the island. But there's an airport and some fishing and some accommodations. Personally I'd hang on to this for a couple years and see if anyone's going to build a big resort there. You also might try to find any charter companies that specialize in travel packages to this island, agencies like that may like to buy this name.