I'm planning to run, jog, walk, stumble and probably finally crawl a 65 kilometre course of my own devising, partially to train up for the army and partially as an interesting challenge. It's quite hilly land. I'm pretty comfortable in the 10 -15 miles category, but I have never even taken on a marathon thus far. Bully for me. Am I being stupid though? How far can someone reasonably go in a day? Any advice?