Tom, remember deer float - you don't have to drag them out when they float. Of course clean up is not too fun after the trip out.
I have also just dressed, boned out the animal on-site and so didn't have the problem of bringing the whole carcass out. Been told that here in Nc that's a no-no, but as they (the WRC) have phone check in now, I can't see how it'd be a problem.
All in all, I have found that most people won't go into the swamps. In Eastern NC most hunters are geared and oriented toward dog hunting, most of the compound bowhunters are just waiting for dog/gun season - the swamps are why they are running the dogs; but being from up toward Wilson, you know that.
One other thing, if the water is high enough and there are enough openings, you might try a small canoe ot a pirouge, they can be made easily and float on a heavy dew fall. You can ask some of the guys from Lousiana about them, plans can be found on the internet - I have fished from a pirouge and while "different" it will go place you won't believe.
Oh yeah, in the summer/early fall watch the snakes.