Mary-
 
Here are some sites with online texts that may have primary sources on
line that contain info on the Dust Bowl era and migration:
 
http://lcweb2.loc.gov/ammem/amhome.html  The Library of Congress
 
http://www.cs.cmu.edu
 
http://www.umdl.umich.edu   U Michigan's Making of America Library may
                                have something.
 
Tim Scarlett