Alland, think Tudor's pics answer that one - one way a least! I flew as a pax from Naples to Key West and back a few years ago. We borrowed life vests from Naples Air Centre and there was some thought of going or coming back direct but as the guys at NAC said: "if you have to ditch, some of your fellow bathers may feel peckish!".
We flew down via Tamiami and back via Marathon and Everglades City (ouch! it was a tad bumpy on the approach and we arrived briefly rather than landed on the first approach, and went round from 50 feet on the second) and all in all it was very pleasant flight, with lovely scenery - and the only time I've ever seen a Twin Otter with floats.