@jorsi I think the way that I'm going to do gump book editing is with htmlgumplings that can handle multiple lines.
This will allow cascading deletes - where you delete a word at the end of the line and the next line's word jumps up to fill the empty space - on the same page, but not cascading deletes across pages.
I'd like to do across pages, but I think it would be too complicated - particularly since you could potentially (unlikely, but possible) have a cascading delete that would lift words from lines across all twenty pages.