I want to share a few tips I've learned.
First: Leave the telemark skis and boots at home. Yes, there are some big downhills but the vast majority of the route is rolling and the extra weight of tele gear really adds up. Find a metal-edged backcountry touring ski and light comfortable boot.
Second: Practice with all of your gear. The race requires a backpack full of safety gear. It pays off to bring it all on training skis. Your shoulders get used to the load, and you get used to finding what you need in your bag.
Third: Eat simple, no-freezable food. Last year my teammate and I packed cookies, sandwiches, energy bars, candy and energy gel. We found the energy gel was the most palatable for our exhausted bodies. This year, that's all we're taking (plus canned coffee.)
Most important: Use half skins. Last year I kept my skins (above) on my skis almost the whole time. It was too much of a pain to take them of and on. But we lost a lot of glide because of it. This year, we've stolen an idea from other veterans. Buy a fat pair of skins and cut them in half long-ways. When they're on your ski, they'll only cover one half of the base (make sure it's the half on the outside of your foot, under the pinkie toe.) When you need to climb, put weight on the outside of the ski edge. When you need to glide, shift weight to the inside. We tried it for the first time last weekend and were amazed at the added efficiency. I'll post pictures our ours soon.