I believe Beth Sarim is also mentioned in the 1975 Yearbook of JW's, which details the history of the organization. It is rather one-sided, but surprisingly, even includes information about Miracle Wheat.
*** yb75 pp. 193-194 Part 3—United States of America ***
CLOSING DAYS AT BETH-SARIM
By November Brother Rutherford’s critical illness had gained ground and he was compelled to have an operation at Elkhart, Indiana. Thereafter he expressed a desire to go to California. So he was taken to a San Diego residence known as "Beth-Sarim." For some time it was apparent to his associates and the best medical experts that he could not recover.
Briefly it may be said that Brother Rutherford had a severe case of pneumonia after his release from unjust imprisonment during 1918-1919 because of his faithfulness to Jehovah. Thereafter he had only one good lung. It was virtually impossible for him to remain in Brooklyn, New York, during the winter and still carry out his duties as the Society’s president. In the 1920’s he went to San Diego under a doctor’s treatment. The climate there was exceptionally good and the doctor urged him to spend as much time as possible in San Diego. That is what Rutherford did ultimately.
In time, a direct contribution was made for the purpose of constructing a house in San Diego for Brother Rutherford’s use. It was not built at the expense of the Watch Tower Society. Concerning this property, the 1939 book Salvation stated: "At San Diego, California, there is a small piece of land, on which, in the year 1929, there was built a house, which is called and known as Beth-Sarim."
Sister Hazel Burford was one of the nurses who cared for Brother Rutherford during his final illness at Beth-Sarim, where he was taken in November 1941. She tells us: "We had the interesting times, for he got to where he would sleep all day and then all night long he was busy with the Society’s business and kept us on the move." One morning about the middle of December three brothers, including Brother Knorr, arrived from Brooklyn. Sister Burford recalls: "They spent several days with him going over the annual report for the Yearbook and other organizational matters. After their departure, Brother Rutherford continued to weaken and, about three weeks later, on Thursday, January 8, 1942, he faithfully finished his earthly course and graduated into fuller service privileges in the courts of his heavenly Father." Later that day the news was sent to the Brooklyn headquarters by long-distance telephone at 5:15 p.m.
How was news of J. F. Rutherford’s death received at Brooklyn Bethel? "I will never forget the day we learned of Brother Rutherford’s passing," comments William A. Elrod. "The announcement was brief. There were no speeches."