As the previous posters have said, you are being too tight and scheduling too much. It would take more than a month to do the route you have outlined. My suggestions are:
Stage at Biscayne Bay not North Miami. You can
anchor or take a
mooring off Dinner Key/Coconut Grove. There are markets, West
Marine and lots of interesting things to do and see while waiting for a weather window. The Library has free
computers for checking the weather although you can get NOAA forecasts with your
VHF Wx channels.
- - You may have to wait a day or a week for a decent wind/wave window to cross the
Gulf Stream. I normally exit Biscayne Bay via Cape
Florida Channel along the south side of Key Biscayne. I leave Dinner Key anchorage just before sunrise (twilight) as it takes an hour to get to Cape Florida.
- - Then I head out to the Biscayne Channel green "1" marker and take a 115° or 120° heading for "Triangle Rocks" (Explorer Chart waypoint). The Gulfstream will set you north enough to get to "Triangle Rocks" waypoint. A longer alternative is to head east and get set north to "North Rock" waypoint just north of Bimini.
- - Leaving Biscayne Channel/Cape Florida at sunrise will normally get you across by late afternoon. Both entry waypoints have good water on either side so even a dusk or night entry is not hazardous.
- - Now you have the option to stop and anchor behind Gun Cay or press on for a night crossing of the
Bahamas Bank. The crossing is a long way and will take a whole day just to get to Northwest Channel Light - 66 nm on either route. I usually divert south of NW Channel Light a couple of miles and anchor in 3 meters (10 ft) on the west side of the shoals/reefs north of Andros.
- - Then just before dawn again, we head north back to NW Channel Light and head straight to Nassau. The idea is to get to Nassau in the mid afternoon after the last batch of cruisers have left the Nassau Harbor Club and they have space for you. I take a slip for one night, the officials come to the
boat, I wash the boat, wash ourselves, fill up the water
tanks (and
diesel if necessary) then walk across to the
shopping market to stock up on anything we forgot to get before leaving Florida.
- - Then head east and south to the Exumas with Highborne Cay or Allens Cay the
destination. You are now on day 4 or 5 after you actually left Biscayne Bay (if you took a night to stop behind Bimini or Gun Cay).
- - It can take a week or more just to get to
Georgetown, Exumas if you stop and enjoy only the high points in the Exumas. And you have to figure the time needed to get back north and west for your return.
- - I would suggest only going as far south as Staniel Cay then heading north again for your 22 days time limit. But from Highborne Cay on the way north I normally head west 285° to the edge of the Exumas Banks then Northwest 316° to Morgan's Bluff, Andros Island. There is an alternative to head up to
Coral Harbor, New Providence then across to Morgan's Bluff but that route is over some serious
coral fields.
- - From Morgan's Bluff, Andros head north to NW Channel Light and then west or north west to Gun Cay or Bimini for your crossing back to Ft Lauderdale. Again timing is critical to allow time to wait for a good wind/wave weather window to cross the
Gulf Stream.
- - You are pushing it to try to do it in less than a month or two. So I suggest reserving a week to 10 days for Gulf Stream crossing weather and then just do the northern/central Exumas before heading back towards home.