I just finished reading Two Years in the Forbidden City last night and decided to do a bit of investigating myself.
Apparently Mr and Mrs White went to Los Angeles (as per this report from the following website)
"Among the dignitaries present were government officials, Consul Chang and his wife, Consul Wong, Anna May Wong, Keye Luke, Soo Yong, a famed actor of the period, a certain Mrs. Thaddeus White, who was Princess Der Ling, and Mrs. Merriam. Radio station KTMR broadcasted the ensuing events."http://www.oldchinatownla.com/history.html
Hope this helps. I'd be interested in hearing what else you find out....