You do not have to attempt this cache, and you'll get the same smiley face for finding a rusty Eclipse mint tin or fake chewing gum in a bus shelter anyway, so why bother? In addition, you'll most likely encounter cold deep water, sinking sand, stinging nettles, brambles, eels, snakes, turtles, the list continues...
If for some crazy reason you're still interested then read on...
You do not need special equipment, but it's up to you how you get there and what route you take. There is no easy way, but you do have choices. Do you prefer cold deep water, sinking sand and inquisitive eels, or do you prefer shallower bog, an ugly bushbash, and deadly snakes?
When setting the cache, the chest waders proved totally useless (perhaps the water was too deep, or perhaps the thick bush would have torn them to shreds? That's for you to decide). Oh, and it's way too far to carry a kayak, and don't even think of trying an inflatable unless it's made of kevlar. Needless to say, the cache was set in not much more than shorts, T-shirt and thongs. However, after a couple of slips, the thongs never made it back, so if you find a pair of Crocs floating near to GZ let us know!
Good luck!