There's a chapter in which one of the characters meets the Beatles in India in 1968. While doing research I came across photos of the ashram (meditation camp) where the Beatles stayed with the maharishi. It was abandoned in the 1990s.
More details on the novel later. For now, here's a current shot of the bungalow where the Beatles stayed:
Here's a photo of John and Paul at the same location in 1968 superimposed over the newer photo:
If you know my obsessive personality, you will know that my chapter set in 1968 will be so historically accurate that Paul McCartney would scratch his head and say, "I don't remember meeting that bloke, but everything else is exactly right, so it must have really happened."