Purchasing through Charter Programs
While I am not a fan of Island Packets, I am focusing on the crux of your question about putting boats into charter. I have been involved in helping owners fix up boats ofter they have come out of the Charter Trade. putting a boat into charter, especially in the Carribean where they are sailing in consistently higher winds really takes a toll on a boat. The boats are in use day in and day out in a very long season. They have a lot of sun exposure which takes a toll on sails, hardware and finishes. They are bounced around and treated as "not my boat".
After 5 to 7 years in the Charter Trade, the boats that I have been involved with have needed some combination of: new sails, instruments and upholstery, and engine rebuild or replacement, replacement or rebuilding deck and galley hardware, bebuilt or replaced refrigeration gear. Often ground tackle, rodes and groundtackle handling gear is in need of attention. Then there is the aesthetic issues. These boats all had a fairly large number of major dings and dents. Wood work was in really poor shape both on deck and below. Deck leaks had been left untended or crudely patched resulting in stains on deck and below.
The point here being that most boats that come out of charter, at least those that I have seen, have needed major refits and restoration.
Beyond that, boats that have been in charter are also often sold at a lower resale price because they are percieved to have withstood a lot of abuse while in charter. The increased depreciation and the required rebuilds have been so extensive that they pretty much offsetting any percieved savings in buying a boat through one of these charter buyback deals.
I have generally thought that the best way to buy one of these charter boats is to buy one from the guy who got it back from charter and has done most of the fix-up work on the boat. These are probably the best deals of all and in the meantime, buy high yeild CD''s and put way a little it each month so that you have most of the cash that is necessary to buy the boat when you are ready.
As to the Island Packet component, there sure are a lot better boats out there for the money (but that was not your question was it.)
Good luck what ever you do.