Anyone use metal detecting gear at vacated USAF facility found on ridge summit, SW mountains of Santa Rosa Island, off Southern California?

Answer 1

Sounds like a rare spot. I'd go for it. Especially if it is not marked, Keep Out.
Consider using a Geiger counter, before you get too involved. They might have contaminated some of the soil with various types of waste. So, just be ware and exercise good caution.