Chuck,
People sail small boats all over the world. Some even live to tell about it. As far as your question about the crossing from Miami (better,... Key Biscane)to the Bahamas, there are OCCASIONALLY relatively calm conditions that would make sailing your boat over, no more difficult than any other 70 mile (or so) passage. Have 2 friends that motored over in April in almost calm conditions. If you go at the right times of the year and can wait for weeks for calm weather, your boat will make it OK... otherwise, make sure that you have an EPIRB, a life raft, a submersible VHF & GPS, and plenty of life insurance (actually, not a bad idea to have all of the above even in calm conditions).