Hi thank you so much for all your searching. Have been doing some also and am now wondering if in fact she was in UK and not USA. Found a Mary W Kenifick in London Electoral rolls from 1950 to 1961 this last one placing her in Queen Mary Hospital . This sounds to be her as story goes she was a Nurse.
Very interested in your find of death Mary Winifred Kenifick in Surrey in 2005 this could well be her as up to 1961 records she was still single. Does the record give any address in Surrey? Again many thanks will pursue this death record. Regards Frances