There is enough water in Florida Bay to make the passage to Moser Channel with 5.5' of draft without difficulty. It is a little convoluted, however, and is best made in good light as there are lots of Fish Traps. If I were going to make that passage, I would head down to the anchorage at the Little Shark River (at about N25 19.735 W81 08.829) and spend the night. From there to Moser Channel and then over to the anchorage at Boot Key is about 45 nm or about 7-1/2 hours at 6 kn. The approach to the Little Shark is pretty easy and there's a good anchorage in the first Oxbow to the north just past the entrance (although it is buggy!). By leaving there by 0700 you should have good light across the Bay and you can pretty easily stay in 10' or deeper water the whole way. You'll need good up-to-date charts and need to keep close watch on your position but it's not hard and you should be able to find a good mooring at Boot Key without difficulty by getting in there by 1600 or so.
"It is not so much for its beauty that the sea makes a claim upon men's hearts, as for that subtle something, that quality of air, that emanation from the waves, that so wonderfully renews a weary spirit."