It All Depends......
Ken,There's really no correct answer! Conditions can vary so much that you could be motoring; tacking upwind or reaching... I have made the trip from Key West to Ft. Myers in about 23 hours, part motoring, part reaching but on a bigger boat. About the best guesstimate you can make is to chart the course and divide the miles by an average of about 6knots. That would be your optimum sailing/motoring in a straight line so allow for plenty of options and allow extra time.Dick