Welcome to the forum!
Not really sure on your situation but i'd advise you to NOT rent a property...or if you have ot intially make it as short as you can.
Sort out a currency broker in the US before you leave, so that you're registered on to their system. When abroad you'll need to transfer money US->UK and so makes sense to have someone/Co in the US who can help you with that. Not saying that you can't do it via a UK broker, but probably more practical the other way round. So much easier if done whilst you have all the documents and a valid address that is required to complete the necessarily strict financial checks for such companies.