I'm new to all this but have been contemplating doing Offa's Dyke next summer some time with a couple of friends and wanted to pose a question..... One of these friends has thrown down the challenge to do the whole thing in just 3 days - he reckons if we aimed to do approx. 20 hrs per day of walking/running we should be able to do it, albeit with very little sleep! Is he mad? We are all relatively fit, in our late 20s and would obviously put in some fairly serious training but interesting to hear any points of view......