Not directly Rupert-related, but here's an interesting story of JC Williamson's early career, and move to Australia, from the Stage Whispers site.
Of course, most of Rupert and Elsie's early theatre career in Australia and New Zealand was with two of JCW's companies, first with John F. Sheridan, and then Julius Knight.
I managed to find Sheridan's grave here in Sydney a while back, while I was on the Bondi - Coogee coast walk!
John F. Sheridan's grave at Waverley Cemetery, Sydney.