Managed to find one of the rarest of the rare, I believe. Virtually the only information that I could find about the Tokyo-born Reiko Takahashi（高橋玲子）was at Idol.ne.jp, and that was only to list the mere two singles that she'd released in 1986 and 1987. I wasn't even sure whether she was an aidoru since I've seen other singers at that site, and they were definitely not teenybopper singers. I could only get some confirmation by going through three pages of Yahoo.jp and discovering that she had been included on a 1988 aidoru calendar that was being sold at Rakuten, and that's now sold out so I couldn't see what the calendar looked like.
Strangely enough, the first version of "Sunset Road" which I heard was one that had been mysteriously sped up, but perhaps there was method behind the madness since it actually sounds rather nice here, too. Maybe the uploader had some Vaporwave ambitions. It actually took me a couple of listens to realize that Takahashi sounded a little too Minnie Mouse to be normal.