Accessible is the key term. There are great flats on both sides of the island, but not always easy to get too. If you have a golf cart, you can run either north or south of town and get access to both sides. I often just take off, with no idea where I'll end up. The backside is a little tougher to get to, because of the mangroves, but it can be done. If you are only going to be there for one day, I'd really suggest you get someone local to take you out. Forget the concept of "Guide", you don't need that. What you need is a local with a skiff to get you where you want to go. Sure, the hotels book fishing trips to tourists for $150 US or so, but I've hired MANY locals to take me out for a few hours for as little as $20 bucks. Bring your own gear,and talk to everyone you see that has a boat. I guarantee you won't have a problem getting someone to run you to a good flat for a few bucks.