Turns out the book in progress was already bugged in an earlier save, so it's disappearance was not related to the notepad. Cleared the bad book out, started a new one (Book C) on the computer, reinstalled the notepad and tried resuming the book. The sim went straight upstairs to the computer and used that for the resume action. Started a new book on the notepad (Book N) and now both stories are available for resume.
Resuming "Book N" on the computer will cause the sim to go to the notepad and continue. Resuming "Book C" on the notepad will cause the sim to go to the computer to continue. Interesting, the memory stick must be tied to the original object it was used with and are not compatible between items.
Writing on the notepad is actually updating the progress, if I let it run a while, cancel and then resume, it shows that progress was made but, of course, still doesn't show any progress during the writing process. If I let it resume long enough, it thinks the book is completed. I can still resume writing it, but it no longer shows any progress bar at all.
So no real progress, just letting you know what I've seen so far in case I'm seeing something that sparks a "Eureka" moment.
