Welcome to Cruisers Forum! Sounds look a good deal to me -- wife gets a good job, you get to take 8 years off and sail around the world. And you're complaining about being away from Montana?!
You are asking about two different things, which you should be sure to keep straight -- training, and qualification. Training you can't get too much of, and people who live in your (new) area will be sure to pipe up with advice. As to qualification, strictly speaking you don't need it to sail your own boat for leisure purposes without paying passengers. Few people would bother with it, although there is a country here or there which might like to see it. If you do decide to pursue qualification, the two which come to mind are (1) the Coast Guard captain's license
(someone here who has one will tell you what is involved in getting it; and (2) the ICC
-- International Certificate of Competency -- which is issued by the RYA in the UK for Americans (a lot of other countries recognize and issue the iCC
, but as far as I know, only the RYA in the UK will issue one to a non-resident. The US is not a party to whatever convention created the ICC so you can't get it there.
The ICC is pretty easy to get once you are a reasonably experienced sailor and have boned up a little on subjects like the Colregs, navigation
, and so forth, which you need to do anyway. It involves a practical exam which you can take on your own boat (if your boat is in the UK). The ICC if nothing else is a good check that you have covered the most basic things. It might help with your insurance
Good luck, and keep us apprised of how your adventure shapes up. You will find lots of like-minded souls on here.