I was sick to death when we spent 14 or so hours on the coach to Germany - maybe you could challenge yourself further by getting down there ALL by bus, for example, stopping off whenever you need to make another connection.
When I went to London at the end of October, we found it easy to navigate around on the underground. Just watch out if you are standing and getting off - some of them are pig ignorant! - my mam had a proper go at a student who had been shopping with her mam because the girl was yelling at us and telling us we were invading her personal space by trying to push our way out of the train.
