If you're REALLY concerned about boat traffic, then get yourself up to Tranquility Bay for lunch one day and go kayaking there. It's beyond the last cut in the reef so there's no through boat traffic. And the reef's pretty close there. They do have kayaks for rent. It's beyond the last stop of Coastal Express but if you were to call them (the resort) I'm sure something could be worked out. Even stay up there for the night if they have room.