I'm thinking out loud here; I don't have a lot to say about this yet other than it seems that the documents here are divided into nodes. The Introductory Node is the top node; it contains a Table of Contents that points to the other nodes in the document.
In moving to an all-cgi environment, in which all HTML is stored in a database and served as needed, it might be useful to work with a Node class, each instance of which can be retrieved and used in as many documents as necessary. Subclasses would include Index Node, CGI Node, Discussion Node, etc...