I would look at Denis Winter's Death's Men. Winter essentially took a large number of journals, diaries and memoirs and used them ( with summaries and quotes) to get an idea of what the normal soldier's experience of the War was like. Winter in a way was doing retrospective interviews on various topics, and some of his discoveries are not what you'd expect ( like, most veterans seem to have had more vivid memories of the misery of standing on sentry duty for long, long hours in the cold winter nights than of the misery of "going over the top"). If there's a source in the book you'd like to pursue, it's well referenced. With the Centennial, I expect some of his sources have been put online since he published in 1979.