Here you can download WordPress plugin
To enable to assign Google Doc for Default Content Type.
To enable to cache Google Doc within WordPress site.
To enable to display Google Doc via AJAX if it is not cached (to decrease page load speed).
To enable to import (purge) individual/all Google Doc to WordPress.
Add Automatic Purge feature.
This feature imports Google Doc to WordPress when individual content is viewed. Once that happens this plugin no longer gets the content via Google Doc Proxy [Beta] and uses the one in WordPress.
This behaviour let you (client) change the content storage to WordPress and complete the content migration work automatically.
This feature should be very useful as content entry work can be started with Google Docs looking like the familia word processing software before the commpletion of development work. Both work can be done parallel and you can reduce the timeframe for site launch.
Downside of this feature is that Ajax feature above should be turned off until all the content has been migrated by the access from search crawlers (Your site must be linked to all the pages to let them do the work for you properly).
WordPress client plugin is managed its code at GitHub (Contribute/Fork WordPress plugin for Google Doc Proxy [Beta]).