I suggest you try for at least 5 days, because the travel time and the "wait to fly" rule won't give you much time to dive during a 3 or 4 day trip.
Going back to Florida or Cozumel may be the best options for a less expensive short trip, perhaps you can wait to try someplace new when you have more time?
Will you be traveling alone? A lot of resorts add a hefty single supplement unless you are booking double occupancy.
Anthony's Key Resort on Roatan has a 2 for 1 option (so no single supplement) but airfare to Roatan can be expensive, and you should get immunizations and take malaria meds before you go - and you don't have much time to prepare. FYI, the cheapest accommodations at AKR don't include air-conditioning and there is a big tax, 18 or 19% I think, added on to the resort prices in Honduras, so keep those things in mind when you are comparison shopping.
You can often find reasonable airfare to Grand Cayman, and the Cobalt Coast Resort has some nice all-inclusive dive packages and they will pro-rate their plans for the number of days you are staying, see the link below.
The price includes accommodations, meals, beverages, 2 daily boat dives, unlimited shore dives, airport transfers, taxes, and hotel services charges. But again these prices are for double occupancy and the single supplement will be brutal and there is a surcharge for diving Nitrox.
Southwest recently started offering daily flights to Grand Cayman from Fort Lauderdale with 2 free checked bags - so if you can fly to FLL on Southwest that might be a good option.
Dive Packages
Grand Getaway Special – Starting at $1,650
Valid for Travel January 1, 2017–December 16, 2017
- 7 Nights Accommodation
- Breakfast, lunch, and dinner (begins with dinner on arrival day through breakfast on departure day)
- 12 morning boat dives
- 5 drinks daily (house wine or beer, well drinks, soft drinks)
- Shore diving is available on our house reef behind the resort (weather permitting)
- Complimentary use of dive computer
- Complimentary Wi-Fi
- Welcome rum punch
- Manager’s cocktail reception (usually Monday evenings)
- Airport ground transfers
- Resort fees and taxes