Well, there are hundreds of people on this forum who are more capable of answering your questions than I, but here's what I can offer:
1. Since you posted in the
monohull section, my
advice would be a boat of at least 36 feet, if you're going to be packing in a crew of 5 or 6. And four of them better be very good friends. I own a 32 footer, which ostensibly "sleeps six," but four of them better be married or at least hopelessly in love.
2. I bought my boat last year. I found a tremendous number of
boats in your
price range on yachtworld .com and sailboatlistings.com. The former is for brokered boats, the latter is not.
3. If you want to learn more about
navigation, I highly recommend taking at least one course with the
ASA or US Sailing. I just passed the
ASA Coastal Navigation course and found it very useful - despite the fact that my boat has two chart plotters, and counting my
Iphone, I have a total of four
GPS systems on board at all times.
As for sailing the
Caribbean, there are many far more experienced folks than I on this forum who, I'm sure, will be able to direct you to online resources, but my thought is that if you're a guy in your younger 20s, why not just go down there and do it?