I can't tell you about the waters in Florida where you live, but I'll take a stab at some of your other questions.
One of the best things about the propulsion system which is called the "Mirage Drive" is that in an instant, you can collapse the fins up against the hull. This means that if there are obstacles in the water, or if you are temporarily unsure, you just separate the pedals, (push one all the way forward) and then the fins will be up against the hull as in the diagram below:
You can also pop the drive completely out of the kayak in a matter of seconds. It clicks into place like a seatbelt, and to remove it, you click two levers and up it comes. It's that simple. You will want to avoid hitting logs or rocks with it, but you don't usually have to remove the drive for those types of obstacles.
As far as switching to paddling... that doesn't take any time at all. You can simply grab your paddle, and you're switched to paddling. By pushing one fin forward, you end up with the fins against the hull and you're done.
The one thing that we do, when we are beaching the kayak, is we pop the drive out before we take it into the beach. This prevents us from ever having any damage to the drive system. Others leave it in, but we're extra careful. You will need the paddle to back up if you get in any tight places, and because it sits securely on the edge of the boat, it's easy to keep it with you.
I hope that helps a little bit. The one thing that I'll add. If you're moving from your Re-Vision to the Hobie Revolution with Mirage drive, you'll almost never go back to paddling. The Mirage drive is THAT good!
My wife usually uses the Revolution, and I use a traditional sea kayak. I'm in decent shape, (much better then my wife who is in average shape) If we race, she is very close to the same speed as me. This, despite the fact that I have better fitness, a more efficiently designed boat, and a lighter boat.
Here is the information on the Mirage Drive from the Hobie website:http://www.hobiecat.com/kayaking/miragedrive.html