I just discovered that Lois Crisler, one of the photographers on White Wilderness had written a book at the time about her experience in the Arctic, called Arctic Wild. I doubt she discusses directly the actual production of that True-Life Adventure but the content of the book is probably directly related to the movie anyway.
The Denver Library contains Lois Crisler's papers. If one of you lives in Denver, it would be great if you could have a look at those papers (especially the correspondence and the journals) to find out if they contain anything about her work for Disney.
The same is true if you live in Washington, since the papers of her husband Herb can be found at the University of Washington. They worked as a team.