We car camped there a bit at the end of a canoe camping trip in the Everglades and I didn't get the impression that the area was very conducive to stealth camping, but it might be possible.

The campground that we stayed at when we were there sucked. We paid $40 to pitch our tent in what amounted to a driveway. At least the showers and other facilities were nice. Since the weather was too bad for the dive boats to go out there were open rooms in motels and we found one at a good rate. We decided that was a better deal than camping in that case. It was just luck that there were openings though and it would definitely not be something you could count on.