I've read many-a-post regarding sharing database tables between Drupal sites, but none that answer the question:

If I wish to share all content (regardless of type), but no site configuration variables, between 2 drupal installations, which tables do I share?

I'm trying share the forum data between two sites, but I can share all data types if it's easier. I understand there are other tables that are important to share (e.g. sessions, users, etc). I need two sites that share data, one with a highly-customized Drupal, Pixture Template, & Advanced Forums and another site that is bare-bones template with default Drupal Forums.

Any hints are appreciated.