Out for a late Sunday afternoon walk without another person in sight, I turned around when a voice called out, “Move to the left.” That voice, in one of those so English of accents, came from a policeman wearing the stereotypical bobby’s uniform. Out of seemingly nowhere, a green Range Rover quickly approached me on the Long Walk, as the 2.6-mile-long pedestrian path from gates of Windsor Castle through the 5,000-acre Great Park is called. As the car came closer, I realized why I had been told to give way. The driver was none other than Queen Elizabeth II. She quickly passed and was off to one of her exclusive retreats on the Windsor Castle estate. My royal encounter—one that occurred during a pre-pandemic visit—could be yours. The queen always spent considerable time at Windsor Castle, which is always described as her favorite residence. In earlier years, the late Prince …