Hi STEVEHH,
there's nothing wrong with the route you are taking as long as you understand the advantages and disadvantages of that route i.e the time it will take you to convert, costs, etc. I get the impression from your post that the present job probably pays you more than most f/o's will get, so also be prepared for that drop in pay.
My Advice to you is this, make good friends in your workplace and the industry you are in at the moment cos when the going gets very tough, in other words, when all is done and dusted, and you are waiting for that flying job, it is those people you can turn to for a job whilst you are waiting.
A close friend of mine took the very same route you are about to take, and he did well when he came back to the UK, first time passess etc. Have you thought about distance learning at a school in florida whilst you are doing your flight training at Phoenix east? That way, at least you are flying and getting parts of the ATPL exams done, a lot less to do when u get back theory wise. Just my thought. Either way good luck with it.
HP