i just located a page that lists "primitive" campsites around the state, but i have not tried any of these out YET:
Primitive beach campsites include Cape Sable, Middle Cape, and Northwest Cape in Everglades National Park (only accessible by boat or kayak), or the Alligator Creek campsite (also in everglades national park), which is only accessible by kayak. Be aware that if you camp at Alligator Creek there is a 90% probability that you will wake up with large alligators tanning around your tent... just a heads up. It's a beautiful paddle out to that campsite.
There are also primitive "chickee" campsites all throughout Everglades National Park... these are man-made structures in the middle of Florida Bay, Whitewater Bay, etc.
There is no real primitive camping in the keys. Everglades National Park is your best bet.
Hope that helps,
OMG! it sounds like alligator creek is aptly named - LOL! thank you dave for all of this information. i cannot wait to experience a few of these.
take real good care,