Is it reasonably possible to cultivate a wide variety of mushrooms in a place like Arizona or New Mexico? I'm not really talking about the mountains though, I want to know about the hot dry areas. It seems quite possible if someone had a nice greenhouse.
You need rotting wood, lots of fertilizer, and lots of humidity, it also needs darkness. You could build some kind of a mushroom hut. It would have to keep the moisture in. You'd also have to keep the hut from getting too hot. I think controlling the heat and keeping the shrooms moist would be the biggest challenge.
Mushrooms are very finicky. I have designed and built massive aluminum heating / cooling / filtration units for mushroom farms. The temperature must be kept very constant, the humidity needs to be constant. The manure must be moist.
In areas that mushrooms grow naturally it would be an ideal area to setup a mushroom farm if that is what you are aiming for.