Everything you heard about Barstow is true. I would not recomend to live there, althou many soldier live there. Your next choice is Victorville, about 70 miles away from Ft Irvin. That is a nice place, but do you want to travel 140-150 miles every day? So, my suggestion is live on post; is not that bad, some housing are pretty nice.
When they say Ft Irvin is in the middle of nowhere, well this is literary in the middle of the desert. For 30 miles is absolutley nothing, and then is Barstow, and then nothing again, until Victorville. On the other hand, Ft Irvin is half away between Las Vegas and LA, so when you get off you have places to go.