It sounds like the following may/would be helpful for you:
- Creating Document Tours - to create a tutorial explaining various parts of a document to non-developer users.
- Adding metadata such as descriptions/comments to tables/columns. This has been requested in Add comments in table and https://github.com/gristlabs/grist-core/issues/98. Would you say those requests partly match what you want?
- If you add
?style=light
to the end of the URL, much of the interface is hidden, including the right panel. This feature needs documenting and polishing.