Lanterne Rouge, glad you enjoyed your run. I know that area well, it's my local patch. It's extremely dry at the moment, as you no doubt noticed. You'll have to do the same route in the winter one day - bring your waders! How often do you get up this way?
Like sbrt says, you seem to have the kit sorted. I think you'd probably need just about the same kit for a couple of hours or so - mebbe a few more jaffa cakes, get used to drinking from streams occasionally?