Sorry i have no insight on the process for conversion in the USA, i have a friend who did it, and for whom it went well, it does take time, and of course, money.. yet a lot less than you would spend in the UK.
Second thing though, do you have an EU passport? if not, forget about working in europe, take your experience to the middle east, asia or South Africa for good shift work, especially with your flight time (IE king air, very sought out right now in Africa).
The King Air 200 is not a transport category aircraft, so you need to do all your ground school plus IFR flight test plus ATPL / IFR written exams. check out the UK CAA web site they have all the info.
Try Netjets Middle east, rather than europe, you are going to save at least a good year for the conversions. same aircrafts, same pay, if not better.
cheers