Am from "up north" and don't get down to London much. Am staying at Blackfriars for 4 days and was wondering from there what will be my best route to the start and also wondering what is the best travel option to purchase. Would it be an oyster card or I hear you can upload travel onto a debit card. Is that any good and what areas would I need for general travel round the sites before and after, expo etc. Any advice?