Keep in mind that if you've had your license for the typical 4-6 years, something new has entered the scene: Real ID. This is a TSA requirement that states "Know their citizens", i.e. have better documentation for people to whom they issue licenses. So as a one-time thing, everybody has to renew in person and bring more paperwork than was required before. Even if they would normally be eligible to renew by mail.
I presume you know about PMBs and the ease of mail forwarding.
So you may need to make some of your "world traveling" happen in a US state. Some marinas are built for live-aboard boating, where the boat is the occupant's primary residence and mailing address. The good news is, the moment you start getting bills and whatnot at that address, you can go to the DMV and take that as proof of residency right away. Most states do not want some nonsense like "you must be here 90 days to establish residency"; they want you getting your in-state license pretty ASAP after you move.
Also, most states will honor your less-than-6-month-expired license as proof that you did, in fact, pass a driving test at one point in your life; so they won't hit you with the full standard of driver competency testing they give to new drivers. But don't put this off.