The walk from the main pool to the West End of DTD is probably about 15 minutes. You can exit the back of the main building, just follow the hallway that is near the magazine/book area of the SSR's gift shop and you will exit by the golf pro area, just as if you were going to the ferry dock. Follow the path away from SSR, cross the footbridge and hang a left. Keep following the path and you will arrive at DTD. If you go right after the footbridge, you will end up at OKW.
It is a nice walk to/from DTD and the path is usually deserted, at least it is whenever I go.