There is one book on the subject, and it’s excellent: Nazi Prisoners of War in America by Arnold Krammer, a Texas A&M professor. (ISBN-10: 0812885619 /
ISBN-13: 978-0812885613)
Includes some rare photos, as well as interviews with the people who ran, and inhabited, the camps.
Many German prisoners had fond memories of their time in the US camps, and credited what they learned here for their successful careers after the war.
I read that a large number of them stayed in the US after the war. Germany was in ruins, no jobs or income.
Don’t recall that he ever mentioned being a POW, but my first flight instructor had been an ME-110 pilot during the war.
No flaming liberal here, but what really pist me off was when I read that German prisoners in the south could go to the movies and sit in the lower section, but black U.S. soldiers still had to sit in the balcony.