When you look at the millions of people living in the "Afflicted" areas and the small number of folks infected you can see that the risk is relatively small. It is good to be aware of the symptoms so as not to be misdiagnosed when you leave the area.
Valley Fever is waaaay down on the bottom of my list of things to worry about and we have lived in the Tucson (a very dusty area), for 9 years. I play a lot of golf and worked on our 3 local courses as a Marshal for 5 years. IMHO: The remote possibility of contracting VF is no reason to avoid RV'ing and enjoying all of the wonderful places the southwest has to offer.
:R