I apologise. I had not realised that I had revealed a spoiler. Looking back on it, I think actually I kinda did, or rather the relevance of the game in question to this thread could itself be interpreted to be sort of a spoiler — so I will edit.
P.
Thanks. 
Thanks for those comments - that’s actually what I was thinking of. The puzzles between surviving are probably not going to be much more than “you find the next piece of the map”, and have to find a good way to get from where you are to where the map points.
Meanwhile, my original experiment has become at least three games… the plot of the original game has become a game on its own, minus most of the “survive the desert” and huge map; the second is almost entirely “survive”, and the third game… I dunno. It’s an exercise in “what can this interpreter do” more than anything else, still. Currently, it’s a map editor. It may end up as a hunt-or-be-hunted game. There’s also a rougelike haunting the back of my head…
Experimenting is fun 
I just flashed back to when I played Infidel as a kid. I didn’t have any of the game packaging with me, including the map coordinates provided as copy-protection. But I eventually found the pyramid by exploring a grid pattern and digging in every single damn location.
I think I might have done that with the combination lock in Planetfall once too, though I may be remembering wrong. As a result, it’s made me a little wary of this kind of information puzzles. I’m always thinking “what if someone tries to solve this by brute force? Will they succeed? Will they hate the author as a result?” You can use resource management to discourage brute-force solutions (you had to eat and sleep in Planetfall, and maybe you die in the desert in Infidel) - but that just pushes the brute-force solution into meta-gaming territory - you save and restore when you run out of time.
I’ve never played Roguelikes much, but I’ve always been impressed with the “security” measures they include to prevent metagaming.
Heh. They did much better with, say, Leather Goddesses of Phobos, where brute-force attempts to solve the maze under the Sultan’s palace would certainly fail 
Which was the genius of it, really … it walked like a maze and quacked like a maze, but it was not a maze, rather a kind of password-protected combination lock … thingy.
(Mind you, when attaching the word “genius” to IF, I’ll pretty much always think of LGoP first).
Oh, it was more brutal than that! The comic book and the map told you what the maze was, but inside that was another maze that you had to figure out, with all the blocked passages. It may be a brilliant puzzle, but the first word that would come to my mind would not be “genius!”
I haven’t lived in the desert per se, but I have lived and worked long enough in the northern Sahel to give you some impressions. Of course deserts vary - the Gobi is not at all like the Sahara.
Trying to survive, food would be the least of your concerns. Water and shade are paramount, and your water loss is very dependent on the shade, and also on the amount of activity (no fixed number of turns). So if at all possible you would travel at night - having to deal with the cold - provided you could find a good shelter to sleep under. The first time you might survive for two days without water, but two days without + a drink wouldn’t get you back in that shape.
Sunlight would burn your skin, and both shortage of water and heat would make you dizzy, making you lose track of directions. Apart from that directions are easy: at night the bright starry sky, during daytime the sun that stands straight east or west (except at noon). Progress is very dependent on the environment - loose sand is very hard to walk (or drive) in, and climbing sand dunes, sliding back all the time, can be extremely tiring. At daytime, hot sand or stone will burn your feet if proper footware is lacking. The openness of many areas will be very discouraging: seeing no shade means a day of walking will not bring you to any, because you can see farther than you can walk in a day - or later on creep in a week.
So all together, one thing to model would be deteriorating shape - loss of energy; pain impeding progress; dizziness; blurring vision through heat, thirst and too much light; loss of sense of time; eventually loss of the will to survive.
Now with a camel the story would be rather different…
Sounds like
Shade
got it about right.