Another Idea
When you figure out what boat that might be, I can't imagine the ideal boat for a 1 year journey, is going to match what you want to keep for the years following that journey.Maybe your ideal boat is one you can rent from Sunsail or the Moorings for an extended time. Then you can go something larger then you might otherwise afford, and can save the time breaking it in, if you jump between the areas that they serve. If you can do somewhat less than a year, to avoid their Christmas peak season, you can probably get a deal that would make you think twice about owning. When your done, return the keys, and think about something smaller for weekend sailing.Actually the first reason that came to mind to suggest this, is the distance you seem to want to cover is out of the question in one year, if that includes the time to break in a new or used boat. You don't need that to add to other things competing for your time budget, like developing needed skills, choosing ocean crossing times during the year that are favorable, and just staying put a few weeks or months at a time when you discover a dream locations you don't want to leave so fast.Both Sunsail and Moorings rent Beneteau's that are ocean capable, although they are not equiped to do that (extra safety gear, etc.) without special arrangements.I recall renting a 40Cc that would be very roomy for two people, includes lots of storage space if you use the second birth for storage or keeping up with a hobby (art ?), was fast, and easy to single hand. Held about 45 gallons of fuel, 130 gallons of water, and was just darn easy to dock and sail even though it was 40 foot.Thats my 2 cents, there's whole books on the subject that have far better advice.