"then island hop to"
Crossing national borders, you will want a "flagged vessel". If you are a US citizen that would be a federally documented
vessel, not a state registered
one. Don't try the clever dodges, find out the registry laws in your home state, find out what provision they make for federally documented vessels, and often you'll have to do both. And carry a substantial liability insurance
policy, and sometimes medical insurance
as well. (Some countries want to make sure you won't be a medical
expense to them.)
Make a list of all the places you might go, look at noonsite.com to see the rules for each one, because they are all different AND they change from time to time.