Generators yes, but the iron would be so much easier to gather elsewhere, the industrial zone is the best source of iron aside from mining. Food would not be there I don't think, at least not in any amounts greater than what you would find anywhere else.
The dart gun/tranq gun idea is interesting, maybe instead of going the gun route you find a craftable formula for for the chemical used in the darts that way you could adapt it to your cross bow darts. Or devise a way to make a wide area chemical spray with different effects such as calm/sleep/attract/enrage depending on what you need. I could see using the gas mask in conjuction with a chemical depressant of some sort to tranq the zombies when looting cities/towns instead of having to make a bloody mess of everything.
You could also use a different chemical to attract food source animals for hunting purposes. Attract them, then tranq them and then kill them and harvest venison for everyone.
I like to think specialized areas would have specialized loot. if all you can get is more of the same stuff there reallly is no incentive to going to such an area.
With the randomness of zombie spawns and attacks, surviving is more luck than skill based anyway. I mean what if you are creeping through the zoo picking up every scrap of metal you find while not engaging the animal zeds, when suddenly a wandering horde spawns and heads into the zoo? Then you are pretty much screwed regardless lol unless you have a big party of friends.