First open all CD files at once; this will allow you to easily ctrl-arrow jump to each CD break and trim it til you're happy. You can even simultaneously trim both files at once; this is a huge time saver.
I was able to make tight gaps for ordinary reading, and leave longer gaps for chapter breaks.
Then Save complete audio.
Then do pause detection, correct any mistakes, and File/Save Split.
This literally got my process down to five minutes for thirteen CDs.
I don't see how that is different to what I advised:
If the book is divided into arbitrary pieces (not chapters), eg. CD tracks or cassette tape sides, edit out any "This is Audible", "End of side 3", etc. Edit each individually, then "Save complete audio" using Control-W, to make a trimmed MP3.
Now join all these trimmed MP3s into one file, using File/Batch/Join to file
Open the combined file in the editor.
Special menu, "Pause detection"
I don't understand "You can even simultaneously trim both files at once; this is a huge time saver."
How fast it is to open depends on how you launch the program.
I have it set to use a single keystroke to open MP3s in MP3DirectCut.
Or in file Manager, you can do it with a right click. Within MP3DirectCut, open from its file menu.
Maybe I misunderstood you.
I assumed you suggested trimming the CD start and end announcements in the CD files one at a time.
This is how I did it on my first pass with unsatisfactory results.
I am suggesting opening all the CD files at once, simultaneously, including the 'end of CD 2' with 'this is CD3' in one trim.
This was a tremendous help as it allowed me to preview the complete gaps as they would sound.
EDIT:
For clarification
When you first open, when you see all your original CD files - open them all at once (shift select).
You will get a book-length file with cues at the CD file breaks.
Use ctrl-arrow to move back and forth. You can trim 'end of CD 2' 'this is CD3' as if they are one passage.
I hope that is clearer; sorry for any misunderstanding.