Valley Fever isn't really a laughing matter, though like many health-related things it's often used as a hammer when really it should be just another should-be-routine issue to deal with.

There's some evidence that many people living in the San Joaquin Valley have been exposed to Valley Fever. It's just everywhere, and those exposed to dusty conditions or who work in the dirt (such as ag workers, construction, even garden work) stand a better chance of getting it than most. If you live in the southern or western Valley for a while, and spend time outdoors especially where it's dusty, there's a fairly good chance you've been exposed even if you never got actively sick. There is a blood test for exposure.

Apparently, many people are exposed but don't develop symptoms; some get flu-like symptoms that eventually subside (and are often not diagnosed as Valley Fever - the blood test is needed for a definitive diagnosis in milder cases, but is seldom done); and some (a minority, but not a vanishingly small one) get it badly enough to be permanently injured or die, especially if it gets into the blood which is nearly always fatal. Nasty stuff. As a fungus, there are some treatment options, but the ones who get it bad often are not identified as having it until it's too late. After many years, CDC finally started looking at it a couple of years ago, so better treatment might be available someday.

Again, chances of this being an issue in Niles Canyon are very small. Wrong climate, even though careful enough testing can probably find spores in the dirt (they're everywhere, but don't seem to be as nasty everywhere - good research hasn't been done to figure out why). You've identified plenty of better issues to attack a project there with.