I’m glad someone has mentioned Road to Wigan Pier, the first half is an amazing piece of social commentary, though in some respects Priestleys ‘English Journey’ is a broader reflection on the lot of the working classes at the time. Second half of WP is a bit more confusing, you can make your own mind up.
Down and out is amazing as a piece of journalism
The whole lot, including the essays, are available to all free online
http://www.george-orwell.org/
for what its worth, I think that reading his work chronologically gives you a really good feel for the ‘journey’ and helps you appreciate how his ideas formed better.