I've got about 2000+ audiobooks I'm trying to tag, so streamlining my workflow is pretty important. I can't really do much in bulk because what I'm doing just won't work that way. I'm trying to use keyboard shortcuts where I can, but there are a couple steps where I have to switch to mouse, and that adds more time, so I'm hoping I can find a way around that to streamline my workflow even further.
Some of the process I'm outlining here could be avoided except for a problem that comes up when I import a .cue file in foobar2000. I don't know if there is any way to avoid that issue, unfortunately. So I'm focusing on streamlining the other steps, if possible.
Here is my process:
- Start with
File > Options > Tags > Advanced > List Chapters as separate filesUNCHECKED, so the audiobook is listed as a single file.
Ctrl-Ito use a source file to scrape the metadata from Audible
- (Pause in workflow to tweak any metadata to my specific preferences, if necessary)
Ctrl-Cto copy the tag data 
Ctrl-E > Enterto export the metadata as a text file 
F4to play 
- In foobar2000, I import a .cue file I made previously 
- Back in Mp3Tag,
Ctrl-Vto paste the tag I copied before 
File > Options > Tags > Advanced > List Chapters as separate files
F5to refresh, so that the chapters are now listed 
Alt-6 > Enterto execute an action that will rename and move the file to a folder structure that is organized by
Author/Series/Series# - Title
- (Pause in workflow I exported in to manually move the .cue file and mp3Tag.txt metadata file from Step 5 from the source directory to the final directory--if there is a way to do this in the action above, I don't know it.)
File > Options > Tags > Advanced > List Chapters as separate filesto prepare for the next file.
Explanations for some steps:
 this is necessary because of Steps 7-9
 necessary because if, god forbid, this whole process gets undone by some mistake, I can re-import the metadata that is tweaked to my specifications without going through the whole thing again.
 I have foobar2000 set as the default application for opening .m4b files, so this will open the file in foobar2000
 because the file I'm working with isn't chaptered by the method Mp3Tag recognizes (Nero, I believe?)
 The reason I do this is because importing a .cue file in foobar2000 wipes all the metadata except for the title and artist that are in the .cue file. If the .cue file has no title or artist info, all metadata is wiped completely. If anyone knows a way to avoid foobar2000 from removing the metadata, most of this process could be avoided
Obviously this is a fairly convoluted process. Steps 4-9 wouldn't be necessary if foobar2000 didn't remove all metadata when you import a .cue file, but I can't find another app that will let you import chapters in Nero format without re-encoding.
Why import the tag data from Audible BEFORE the foobar2000 step instead of after? you may ask.
Well, the chapters will keep the FIRST metadata written to them, even if you subsequently change the album-level metadata. This can result in the chapters not reflecting the same metadata as the audiobook/album. So, if I make all the tweaks before the metadata is wiped by foobar2000, and then paste the finalized, tweaked metadata in the wiped file afterward, I don't have to make any tweaks on the chapter level, which ultimately saves me a bit of time.
Step 13 could be avoided if I knew how to copy/move any supplemental material stored in the source directory to the destination directory at the same time I move the audiobook file in Step 12.
Ctrl 1-10 can be used for custom keyboard shortcuts, but that appears to be only shortcuts involving external tools, which doesn't do me much good.
If anyone has any suggestions (or questions that might help formulate suggestions) I'd be grateful.