if you dont have tbw it should be easy as hell. the tbw side is the bitch!hear is another trick use a pull string or even an old speedo cable or a fish tape. we electricians use these. but stagger the wires when taping them up . this keeps the head small and is easier to get around the bends.
tape all wires together and tape to string wire fish tape what ever you may use . should only be 5 minute job. give or take.