So I'm looking at maps, in real life as well as the "known" fallout universe. Death valley isn't that far away from Vegas. Really inhospitable place obviously, but I can't help but wonder if some kind of unique adventures could have been somehow found there for the Courier. Robots could probably survive out there just fine -- the question would just be "why."
The dry heat makes the Mojave look almost cuddly. Water needs would be much higher. I've heard something like 32 liters a day.
There's supposed to be an oasis or even a waterfall up in a death valley mountain area. Even if it's just a myth it doesn't have to be in Fallout.
There's not much out there for the war to damage, but I doubt many nukes were wasted on it, so it might be rad-free, barring nuclear tests.

It could work. Like a thriving secret society untouched by the nuclear war because of an unknown oasis in Death Valley.

You could probably add a quirk like they expel people in their society who has done a certain something and you could see them wandering the desert or as npcs in New Vegas/Mojave.

A few more factions could also work like a community of mutated humans who act more like cactus, needing only minimal water but are hardy individuals, a group of prewar robots/cyborgs and/or an underground society of humans who created their own utopia.

Once I found out about a real-life legend of a death valley waterfall, I couldn't help but think of the implications in the fallout universe.  An oasis surrounded by the harshest pre-war environment in the country.  But without being targeted by nukes, this would grotto would instead be closer to a utopia than a death valley.  It's full of real-life ghost towns too, providing fallout-like ruins already.  

Death valley grotto cyborgs are an interesting idea.  Cyborgs are something that could easily have been more common than they actually seem to be in the fallout universe.  Implants exist in NV, but as far as I know, nothing to actually get the player some full-fledged (visually noticeable) robotic limbs.

This is apparently Death Valley National ParK:
https://www.youtube.com/watch?v=qaHySOqiygk

If there was a death valley in fallout universe, it would be hard-as-nails to travel through (considering the extreme heat alongside the radiation from the nukes) but with a assload of great loot to compensate, with some sort of robot utopia like other comments say.