Need default play order rearranged to play ripped tracks after my personally recorded tracks.

I am rearranging all J.R.R. Tolkien audiobooks into 1 big audiobook.
To read/listen in chronological story order, the tracks from each book need rearranging.
(So you jump from book to book very often.)

QUICK VERSION:
1.) Bought & ripped 7 audio books (1888 tracks) into 7 different folders.
2.) Made separate, sequentially-numbered folders (188) to rearrange the tracks into the desired play order.
3.) Moved tracks from original 7 folders into correct sequential folder to create correct play order.
4.) IN EACH (of the 188) sequence folder,

 I manually recorded myself giving an explanation as to which book the reader/listener has jumped,
 with filename beginning with underscore to guarantee correct play order.

5.) PROBLEM: In each folder, my manual recording (newest) plays last instead of first,

 even after smallest naming convention & re-tracking to smallest track number.

LONG VERSION:
Much of the storyline from each of Tolkien's books happens simultaneously with each other.
If you want to read the whole story, in story order, you need to swap books 188 times,

reading a few paragraphs before swapping books. (That makes it seem like one big book.)

I already created a single-volume book like this for the Kindle app.
In the Kindle app, every time you change books there's a header page saying,

"You're now reading from [BOOK]".

To do the same thing with the audiobooks, I simply made 188 folders (since you swap books 188 times.)
Using my Kindle creation, I moved all the audiobook tracks from their respective book's folder

into the "Sequence" folders.

This puts everything in the correct order for reading the entire Tolkien saga in chronological story order.
I then made an audio recording of myself to be the equivalent of the Kindle header page,

with me recording a small MP3 saying, "You're now reading from [BOOK]".

I named each of those 'header' recordings "_SEQxxxINTRO.mp3"

(with the 'xxx' being the folder/sequence number.)

(All original audiobook tracks are alphanumerically later.)
Then I moved each 'sequence header' MP3 into the correct 'sequence folder.'

Because the filename is alphanumerically earlier than the audiobook files, it appears first in the file structure.
I figured that alone would make it play first.

In every one of the 188 sequence folders, the 'header MP3' is listed first in Windows Explorer,

but plays last when I click "Play folder with Media Player" (or "Play folder with Winamp".)

These homemade MP3s had no track info, so I pulled the entire parent directory into MP3tag,

sorted them by 'path' (which put every title in correct order), then used the 'Auto-numbering wizard', both with & without 'leading zeroes' and with & without 'total track count.'

None of that made a difference.

It is very obvious that the PC is playing the tracks by creation date,

something I've only seen as a problem with my FAT32 USB/HDD when I've plugged it into my
car stereos. (But NEVER with a real PC.)

When faced with this in the past I've re-ordered using DriveSort to fix play order by tricking the creation date.

This time, with the PC, it doesn't make sense.
I'm currently running DriveSort anyway, but I figured I'd post for any insight.

Best case scenario: I'll come back in a few & report that DriveSort fixed the problem.

RESULTS OF DRIVESORT:
I made a copy of the entire 6GB Audiobook & used DriveSort on it to get them into the correct order.
It worked fine.
Now that I was finished with it (I thought), I copied the entire Audiobook to my backup drive (post DriveSort version.)
The new copy has reverted to playing them in the incorrect order.
I went back to the source & it still plays them correctly.

WTH?

Usually, you have to fill ALBUMARTIST, ALBUM, ARTIST, TITLE and TRACK to get a decent order of files.
If you have only the track number, you have to make sure that the player also sorts by this criterion and not first by ALBUMARTIST, then by ALBUM and last by TRACK. Because then empty fields cannot be sorted as they are all the same or actually missing.
Perhaps then your player resorts to the creation date.