Hi Juliet, and welcome to cruise-chat.com.
I have two resources for you. The first is a map of Half Moon Cay
, from HAL's Web site, showing the locations of the cabanas and other points of interest on the private island. As you can see, the cabanas are in a long row, with some a lot closer to the action than others.
The second is a link ot a photo montage
someone once referred to me, supposedly showing the relative positions of each cabana.
Hope this helps, and enjoy your planning!