Yes, as with any endurance event, staying hydrated and fed is essential. It's bone-dry over there (avg 10% RH) to begin with, and it's harder to maintain hydration at higher altitude. Drink, drink, drink. They serve HEED at the feed stations, so I would recommend getting used to the taste of that unless you're going to have your own support car.

But let's not kid around, no one is going to complete this event by "just" staying well-hydrated. Unless you aren't really serious about finishing, you've got to go into it with a considerable amount of training, and even that may not be enough.