I agree that is the easiest way to get to the Waldorf. You don't have any tube transfers. It's about a 5 block walk from the Covent Garden tube station. You can grab a pasty as you walk by the shop just north of Covent Garden. Blocks are short, and the walk is quick. Just be sure you have a London map with you. You need to walk thru Covent Garden, and it isn't a straight line to the hotel.