Dissertation Reviews offered a series of articels on visiting archives in China and Taiwan.
Charles Kraus' "Researching the History of the People’s Republic of China" (A Cold War International History Project working paper)
You can look up Archives at Yale for unpublished manuscripts and archives related to China in the Yale collections. Also check out China Primary Sources Subject Guide compiled by the Yale University Library Manuscripts and Archives.
For China related materials in the YUL Divinity School Library, see the China Resources at the Yale Divinity School Library, including Papers of Missionaries to China and The Nanking Massacre Archival Project.
***Please refer to Guide to Using Special Collections at the Yale University Library to access special collection materials