OK, I doubt this'll blow the cover off the place:
Grassy Key, mm 58 (?) there's a road heading South off the highway called
Edgewater Road. Follow that road South, past all the no trespassing signs
and it then bends to the West. Follow it all the way past a big old
homemade looking house until the road turns into two tracks in the dirt.
Follow it to the end - the flat will appear on your left of course and there
is or at least there was a rope swing hanging from a tree. Beautiful place.
Soft wading for the first 300 feet or so then the bottom firms up nicely.
In my mind I call it the Gilligan's Island flat.

bruce h