Thanks for your response to both this and the related question about "Adding New Sections to a Page"
I think I understand now that I really need to just build a traditional back-end using the Data-Dssist/Security-Assist extensions.
I guess I just really liked the interface of PowerCMS - I think it would make my non-tech customers feel quite warm and fuzzy!
So the last question before I abandon trying to use it for THIS project (I got others in mind!)
Can I somehow integrate the two backends? For example, they sign into PowerCMS and then can link to my custom backend from within PowerCMS? maybe even use the same authentification?