Survival

Hey!
You know that FFHtR planed as sandbox roguelike?
well, at least you know it now. Of course, we would have story and drama, but it wouldn't be center of gameplay.
So, survival is cornerstone of such type of gameplay.
What it would be:
Food, temperature?
Any ideas?

Update:
From one hand, it easy to create survival, make player to collect branches for fire, finding clean water, keep in mind temperatures etc
well, Such basic survival sounds good for the the start of the game, but later, you know, such micromanagement doesn't fit well future epic adventures and would become simply boring.
We should find some nice mechanics to fight it, and to my mind it simply impossible or
we can allow player to "overgrowth" such simple needs, when character progress at levels.

I vote for the second one.