Heresy? As I'm probably taking a sled as my best guess is over 40kg of kit, I'm currently toying with the idea of not taking a rucksack (or possibly just some Ribz and the side-pockets of my Lowe Alpine Saracen as a backpack for light stuff needed en-route - brew-kit, FAK, SAK etc), and have my kit in bags (duffel-type for fitting on sled).