Anyone who plans to use the train/bus/train/tube/bus route is quite frankly mental.
Many moons ago we played Wycombe away on Boxing day and travelled to game by train. This included getting friends mum to take us to Brighton, train to Victoria. Walked to Baker Street tube station and got tube to Rickmansworth before taxi to Wycombe. Made Wycombe before pub had even opened. Long day but it was a laugh.