Charter Vs. Buying
I think with Dana125''s comments you have now three ways to go:
1. Charter, 2. Purchase and resell and 3) purchase of a smaller cruiser that can be easily trucked. Perhaps another choice is buying a boat that stays in a charter fleet after you are done and you get the charter income (after expenses ;o)
There is a finite cost breakdown for each that I am sure you can work out. First, you have to decided if you want a boat after you sail for a few months. I recently met a couple in the Keys who had their 30ft boat trucked from New England. Very cost effective. They have had the boat a long time (pehaps its paid off) and whenever they want to get away, even if it is someplace far off, they send the boat. Then they have a boat they know and love. The cost for a small boat might be $2/mi. Their cost from New England and back is probably around $6k. Obviously, this is after the cost of the boat. Trucking a larger boat is about $2.5/mi.
Charter is fine if you have the disposable income and you don''t want a boat after this trip. You may be able to negotiate a much more attractive price for such a long duration trip. This will involve a bit of legwork on your part. Lets even say it comes to a grand per week. We will round that off to perhaps $20k for your adventure, depending on the boat and what you can negotiate.
Buying and selling a boat involves lots of costs. First, the costs involved in your search for a boat, survey, yard fees etc. Then upgrades for your trip and sales tax, slip fees and documentation. All this can easily add up towards $10k depending on the boat. THEN when you go to sell, 10% goes to the brokers, the buyer will certainly get you down from your planned selling price and will ask for some repairs. All THAT will cost you $10k or more depending on your boat. I could be off, but I would suggest that buying and selling a $75-90k boat in the islands will cost $20k.
Hope this helps