It can go several ways.
Way one: Take it, part it, profit.
Way two: The person currently in possession helps you. He does the paperwork that makes him the legal owner (having already waited more than three years), pay big money for him to get it titled in his name, then re-title it once he "sells" it to you.
Way three: You do a title search, contact the last owner and beg for a release of ownership document, pay normal money and get a new title.
Way four: You register it in Vermont and get your own WA title (hopefully).
Way five: You restore it just in time for the rightful owner to show up with the title and ask you for his bike back. (this is the least desirable option)