Hi - I got round my first half marathon on the RW 10 week schedule http://www.runnersworld.co.uk/news/article.asp?UAN=99 earlier this year. Following the schedule was OK but the event itself was quite painful. So as the others have said, if you really want to do it, go for it but you'll have to stick to some sort of plan. And don't worry about being at the back of the pack, someone's got to be last and in an event like the GNR, they'll be plenty of folk just out for the scenary and spurring each other round. So what if it takes 3 hours?