Hi efromdc,
What I meant to say is that you can use any of the wp_insert_post args with tribe_create_events. So you can pass in taxonomy args (the event categories are stored as custom taxonomies) like documented for wp_insert_post with tribe_create_events.
By default there is only one category box for events included by our plugin. This is the one for event categories. If the default WordPress category box is displaying, you would have to have added this manually via your theme’s functions.php file or via some other method because we don’t register support for default WP cats in the plugin.
Does that make sense/help?