Just a quick note about Heislerville - I birded the first impoundment, near the end of Matt's Landing Road, last night, and there was not much mud yet, which in a way was nice because what birds there were foraged close to the road, great for viewing and photography (pics later).
But I wish I had gone straight around to the second impoundment, which is completely drawn down and was packed with waders - 75 Snowy Egrets, a Tri-colored, 100+ Glossy Ibis, 25 Great Egrets - and many yellowlegs, mostly Greater, and a few other shorebirds - Dunlin, Short-billed Dowitchers, Eastern Willet, Semipalmated Plover. It was almost dark by this time, but I suspect we'll be hearing more about this spot this weekend and beyond. It seems a certainty a White-faced Ibis will turn up there, and who knows what rare shorebird, the second impoundment looks great for Ruff in particular. Reach the second impoundment by taking Matt's Landing Road towards the marina and turning left after the first impoundment, on the left, onto the sand dike. Turn left again where the dike T's, and continue to the second impoundment, also on the left. The dikes are narrow and a little bumpy, but very passable, use caution though when near other vehicles or fishermen.