I'd like to show players lots of info on how the server works with a /help command.  Definitely too much to dump into the chat box.  Is there a way to accomplish a big scrollabe text box similar to what players get when the press ESC?

There's no way to know when the player presses ESC, as that key is never sent to the server. I don't think you can really make a scrollbox/text either aside from rapidly refreshing the UI created as areas are clicked.

Thanks for the quick answer.  I think I was unclear - I'm not looking to hook the ESC key.  I'd like to re-use that scrollable text box component with server info in it, but show it with my text when a player types /help.  Impossible?

I'm not sure which scrollable text box you mean, but any default UI in Rust is not something you can edit or re-use. Rust only provides a limited CUI to create basic UI elements that have to be refreshed when you want changes made to it.