Provided you have the wx for it then its quite feasible to not plan to sleep much at all - you aim to do it non-stop and just curl up for a kip if people are getting weary.  You do need a set of dry clothes for this, as lying out in the sweaty clothes won't do you much good. 

You also need to be comfortable at moving off track in the dark which requires  a bit of experience - and there are some places in TNP where I wouldn't keep moving once night falls due to bluffage etc, so you need a bit of judgment.

Terra is dead right, that sammies is the way forward.  For my 24hr - 27hr missions I aim to have 1 food item per hour.  Mainly muesli bars and choccy bars and lollies with a few gloop products thrown in.  I also aim to take sandwiches for the 'big meals'.  Its great to stop at about 6-8pm for a sammie and then have another sammie or 2 for breakfast between 6 and 7.  Lately I have used a plastic container of cooked, cold pasta instead of sammies.  This has been the schizz.  You do need that 1 food item per hour and more if it is cold.  The only way your body can produce energy is by eating, and when you are travelling light it is critical that you don't get cold, as its freakin hard tio warm up again.  Regular snacking is the way to stave off the cold.  We do it via the beep on the watch, every hour when it beeps we chug another bite of food. 

 One of the things on these sorts of missions is that you age backwards.  You start as a functioning 20-something* year old with adult tastes, then slowly deteriorate to child-hood where all you want to eat is lollies and chocolate, then you get down to infant level when you are off the solids.  I find at about 22hr+ I will just be on sugary gloops, which I mostly throw up down my top and then spend a few hours crying for mummy.

*some of us are quite advanced 20-somethings, like 20+12