I wanted to follow up on this since I found an answer.
I tried the one suggested and it wouldn't work for me. I found several other suggestions along the same line and those wouldn't work either. Then the tablet stopped charging and I had to send it back for repair.
In the interim, I bought a second one (one for my son). I fought with it for awhile before I got it to mount. But when it did it was really, really slow, and the only thing I saw was an empty directory called Playlists. I played with it off and on as time permitted and I was willing to put up with the torture. Finally, today, I stumbled on this page
. It not only works, but it's much faster, and it shows all of the files on the card. I just backed the card up, and I'm copying some music to it now.
Now all I need to do is find a way to run apps from the SD card without having to root it first.