Some good training tips above. I honestly think mental preparation is just as important as physical. That tundra walking sucks, no way around it. You average about 1mph when walking, sometimes less if you’re in the hilly portion. Plan for a whole day to make it to the five mile line when you’re hauling all of your gear in. You’re going to be wet, cold, then hot, then cold again….did I mention wet? You’re not going to walk in a straight line, the tussocks and other terrain features will guarantee that. Your five mile hike will probably be closer to 7-8 once you zig zag all around the obstacles. Your hips will burn from balancing on one leg. You’ll take twice as many steps, because your stride can’t be normal. It sucks….but it doable. Keep telling yourself to embrace the suck.