I have just finished “Lady Catherine, the Earl, and the Real Downton Abbey”, and I would say that if you are going to visit Highclere Castle, it is a must read. It’s the story of the last four generations of Carnavons, especially the 6th. as told by the Eighth Counters of Carnavon, Fiona, who lives there today.
Fortunately, she had access to an astounding amount of archival material, and people with memories, and she really brings the place and its people alive. Even if you only get part way through the book, it will make your visit that much more interesting.
It is the story of many challenges, social, financial, marital, wartime, and her telling of the ways people coped with circumstances makes a compelling narrative.
Even if you are just a Downton Abbey fan, this will be a great read for you.