How do I obtain the three boxes in the Graves Papers, 1914-1932?
Yes, most archival material is not available via ILL. They typically expect researchers to make the trip to their library. Did you already try contacting the library? I would try the Archives reference librarian, Carol Leadenham. Let her know what you are working on and specifically what you want within the Graves papers (take a look at the container list and the collection guide) and she may be able to give you some recommendations of other sources. It's also possible that they are working on digitizing this collection and she could certainly give you updates if that was the case. It never hurts to check with the librarian!
In the meantime, did you already consult the following sources?
2. Another book you may want to check out is Betty Unterberger's America's Siberian expedition, 1918-1920; a study of national policy. We have it here, but it is currently checked out. You could put a hold on it, though, and you would be the next person in line after it is returned.
3. For primary sources, try the Polar Bear Expedition Digital Collections at the University of Michigan's Bentley Historical Library here:
4. Gibson Bell Smith, an archivist at the National Archives, published a series of articles on this topic. Here is the link to access those:
5. There's an e-book on the history of the American Expedition available at Project Gutenberg that you may want to review as well. Here's the link:
Finally, we have 12 books in our library on this topic. Do a words and phrase search for Soviet Union History Allied intervention, 1918-1920 to see what we have.