Route from SW Fl to Cancun via Key West & Cuba

[teveau169]

Hi! I have a small (31') yatch powered by twin 350 gasoline engines. I have 200 gallon gas capacity the range approaches 400 miles IF I maintain 8 mph! At cruising speed (15-20 mph) I only get approximately 125 miles on that gas.
Any advise on any or all of the following topics will be greatly appreciated:
1. Visa to enter Cuba and travel via boat west toward Cancun, and over land to sightsee and possibly dive;
2. Availability of gasoline at various ports along the north side of Cuba;
3. Any route information from 10,00 Islands to Key West; from Key West to Havana Cuba; from Havana along the north length of Cuba; from western tip of Cuba to Cancun.
4. The best time of year to make such a voyage. I am thinking of October of this year.
I also could use an experienced crew member who wants to see Cuba, etc.
any advise or information especially from anyone who has made all or part of the trip.
Tebeau169