O'Neill told Diamond Previews, published today, that the new book will be set in 1975 in South America.
That's the year Wonder Woman started on TV, initially set in the Bermuda Triangle. Rocky Horror Picture Show was released. They Saved Hitler's Brain in which scientists had, well, you know, in South America in 1968. The Moonraker novel came out in 1954, but the movie in 1979, with a South American evil lair being constructed. Who knows what will be scavenged for River Of Ghosts?