(NOTE: This applies to audiobook series comprised of a single file per book. It may not work for multi-file audiobooks.)
Okay, so, my explorations with how to manage series on an iDevice sort of took me into the realm of other things, which will be its own separate post, but if you want to see how to manage a series so that it at least displays properly in iTunes, here's a quick example of what I did to turn this:
into this:
Short version? Make it a podcast.
Of course, it's a little more complex than that.
NOTE: Some of this metadata cannot be edited once your books are in the podcast tab, so while the books are still tagged as Audiobooks, make the following changes:
First of all, you need the "Album" metadata field to be the same for every book. In this example, which is the mainline series, shorts, and offshoot series from David Weber's Honor Harrington universe, I made the album "Honorverse."
This may cause issues with audiobooks comprised of multiple files. I use chaptered m4b files so I don't encounter those obstacles, but in the Audibooks tab of iTunes, "Album" is used to denote the actual book when you have separate mp3/m4a/m4b files for each chapter or part.
To be honest, I haven't worked with any multi-part audiobooks using this method, so I don't know how it would be best to manage that. I may experiment later. Off the top of my head, it seems the best way to work that is to make the title field of each separate file "Book Title - Chapter ##" and the Album field the series name.
The second thing you need to do is make sure the "release date" field of the audiobook metadata is edited so that the books are dated in the order you would like them sorted. This may not be accurate if the books in your series were not released sequentially, and may require some falsifying of the release data metadata. As you can see in my screenshots above, I have made my release dates a month apart in ascending order.
(Anecdote: At first, I thought I would be clever and date the books according to the in-universe chronology, but since that chronology spans multiple centuries, and iTunes and some podcast apps on the phone abbreviate the year to two digits, it ended up being a big mess. Don't be me.)
Once you have them all in one "album" with sequential release dates, you go into the options tab and change "audiobook" to "podcast." They will move to the podcast tab of iTunes, and should be listed in order, with the Series name as the Podcast title, and each individual book as episodes within that podcast.
The nice thing about making them podcasts is that you have the lyrics tab where you can create custom lyrics and have your book's full description, with a short description in the comments section. This is particularly nice in certain (non-Apple) podcast apps, where you can see the book's description in detail.
More to come later.