Sorry I didn't pipe in earlier on this thread, but I've been away from the board for awhile.
You guys are referring to Passion Island and there are in fact tours there daily. It is privately owned and they cater to cruise ship passengers only. They take them by bus or "jeep tour" from the cruise ship terminal all the way to the end where there is a parking area. They then take a pontoon boat across the lagoon and spend the day at he beach where they are served a full mayan style lunch and activities are planned.
A friend of mine is one of the managers, and he took me out there a year or so ago. It's really beautiful and actually a couple of Corona commercials were filmed there a few years ago.
They used to offer the tours at the hotel, but it wasn't a big seller, so they started focusing on the cruisers and the ship sells the tour.
If you wanted to go out there., you could drive a jeepall the way until the dirt road that goes north past the golf course ends...then see if they will let you go...but you would spend the day with 100 or so of your closest pod friends