If you are going to walk, then I would recommend wearing sandles, crocs, or similar. The going is a little boggy in places, and the tide can come in quickly, so please check the conditions carefully before heading off.
I would also recommend heading over from the southern bank of the Panatana, near the posted parking location. Walking from here avoids the deepest water course.
The cache is a cammo 1.2l Sistema container that, when placed, contained some items that might help to pass the time if you get stranded and have to wait for the next low tide: pack of cards, 3D tic-tac-toe game, magnifying glass, and a hand warmer. There is also a whistle to signal passing ships, and a marble (to replace yours if they've gone missing).