It seems to me that it all hinges on your future employer's needs.
What was the reaction when you said early to mid -May. To me, that's not ASAP...but was it ok for them?
IF so, you probably have enough time to work your way up.
Even if you left by april 1st...that gives you a month and a half...
How long did it take you to get there..??
I'm guessing that your biggest challenge will be catching the right window to get across to florida...
The alternative is to get home and start working...and find a captain and crew to get the boat home.....or some of the other options above.