A part of the Portal to Texas History, the Texas Digital Newspapers Program contains digitized and searchable issues from over 1600 different historical newspapers.
UTSA Special Collections has a large collection of digitized archival materials documenting area history, including photographs, archival documents, and oral histories.
The Paul and Kitty Baker Papers at Texas State (San Marcos) contains material dealing with both of their careers, including work with the Baylor Children's Theater. San Marcos is about an hour's drive away from Trinity.
Published by the Texas State Historical Association, the Handbook of Texas is an online encyclopedia with articles about notable individuals, events, and places in Texas.