Good tips, World Trecker. And yeah, I agree that trip sounds awesome. I've never done anything close to it (2 continents, a handful of countries) but would love to one of these days.
I know a friend of a friend who is, with a friend, going to sail around the world on their own sail boat.
Here's their website. The freakin' trip is, as scheduled, going to last like 2.5 years! But the way they're going about it is a lot closer to how it sounds you'd like to go about it (more down to earth and "roughing it" instead of lounging on a luxury liner).