I found out how to solve my problem.
The file was stored in C:\Users\Dussault\AppData\Roaming\Microsoft\WordPad as Wor83DB.tmp. I was able to read it by opening it in Wordpad.
I found it by reading that the files are saved as .tmp, so I did a search for "extension:tmp" and used Wordpad to open each file from the relevant timerange. Most of them were nonsenical, but this one worked.
I still don't know why two older Wordpad documents that were never saved were recovered and opened on reboot, nor do I know where their data is saved (they're not in Wordpad folder). However, contrary to what many users say online, Wordpad does have an autosave function. It's crude and shouldn't be trusted, but it works.