Hey John - -
The JS API isn't built for this type of work - it focuses on interaction vs. administration. Instead, you'll want to use the REST API. Specifically, you'll probably want the Query Workbooks for User method.
Yes, looks like the REST API has what I need. Thanks for the quick answer.
Server information on published workbooks is also available from the Tableau PostgreSQL database. Google "Tableau Custom Admin View" for good examples to show your server workbooks, who is accessing them, etc.