Florida's castle doctrine allows for use of deadly force if the person feels that they, or someone else are in danger. Also to prevent a forcible felony. This is legal anywhere the person has the right to be as long as they are not committing a crime.
Castle Laws are laws that address the use of force when defending one's self inside their home, or on their property. Some states expand this to vehicles, and the person's place of work. Castle Laws generally include: the places where this law applies, the requirements fro use of deadly force, if there is a duty to retreat, the amount of force that maybe used in defending one's self or others. These vary widely from state to state.