The claim: southwestern Camp William property - east of the old bombing range. Camp was accidentally discovered by a man and his son who were rabbit hunting; they were discovered and apprehended. SW of Tooele.
What it really is: Camp William is a National Guard training site operated by the Utah National Guard. I've taken a look at the site on Google maps and there are no unusual buildings there, and nothing that looks like a prison camp.
As for the claim that a father and his son were apprehended while rabbit hunting on the base, that story is entirely possible since the base is out in the wilderness, and it is not open to the public (considering they do live fire training there, that would make logical sense). Assuming the story is even true to begin with, it's most likely just the result of misidentification, coupled with prejudice due to a negative experience.