How do I organize content based on date field in a Y > m > d hierarchy?
So for Drupal 7: Take look at this description:
http://chrisshattuck.com/blog/how-create-monthly-archive-block-drupal-blog-views

This is basically an explanation of the "Archive" view (disabled by default) shipped with views. Take a closer look at it and copy it to apply a few minor changes.

It gives you a monthly grouping of your content if there is no argument passed. That is actually the trick. Instead of the "created" date of your content just use the date field you have as argument.