Thanks, Katrien! I enjoyed Paolo d'Iorio's book about Nietzsche, Rée and Malwida von Meysenbug sojourning on the Sorrento peninsula in the winter of 1876-77. It gives an insight into the rather austere but generative 'salon' ambiente they spent their days and evening in: https://www.goodreads.com/review/show/1807645897

And indeed, it nourished Nietzsche's most intriguing brand of action research ...