There are no short answers to your questions. Think about how often your local met has predicted a clear forecast and you ended up in a torrential downpour without your raincoat. Hurricane track and intensity prediction, while discussed and studied by the best mets in the business, is not going to provide you with the certainly that you are seeking.

Each day the forecast will get more and more reliable. What you CAN do now it start planning if you have not done so already. Folks in the keys could be affected as early as Monday afternoon, but the rest of us in Florida have a little more time to "hunker down" or hit the road. Make some plans for BOTH scenarios. If you were to stay, what supplies would you need? Start visiting some of the emergency sites for suggestions. If you were to evacuate, where would you go? Who would you stay with? What would you need to take with you?

We are in the "watch, learn, and prepare" phase, not really yet in the "freak out" phase.