easy as 1 2 3
i'm uk passport holder, just bought a klr650 last month in fort myers, florida, and am now in southern mexico... so proof its possible.
to make it quick and easy:
1- make sure the title is in the name of the person you are buying from- if not this the only thing that will stop you from having the whole process sorted in only half an hour- and that person must be present with you when you go to the highways department office.
2- the title must be the original and color. Photocopies mean trouble, money and delays.
3- Your UK license is worthless here, if its not US then they will need your passport.
The guy who sold me the bike in Florida picked me up from the airport and drove me to the Title office and in half an hour I had shiny color title in my name and a new plate for the bike. And of course my bike.
As for the address, they just need one to send the renewal when its due, but certainly do not need proof you live there. Try asking whoever you buy the bike from.
AND you dont need proof of insurance to register the bike in your name, man in Florida you dont even have to ware a helmet.
Im writing this from Playa Zipolite, Southern Mexico, and i regestered the bike in Florida on 17 Feb. Only a month ago.
So dude, get to it and hope to bump into you headin' south maybe, as we head for Guatemala in a few days and south from there.
Give us a shout and let know how you get on