Thanks again for the thorough explanation ... very helpful, and a big time saver.
I have a 32G stick with a single fat32 partition ready to accept some mp3s, freshly converted from a collection of flacs. I am using Debian Linux, and do the conversions with some simple code which I found online.
https://jima.cat/convert-flac-to-mp3-on-the-ubuntu-command-line/
THX for the heads up about capacity .. I will experiment with amounts, but don't plan on a whole ton of files -- I want to listen to the music, not watch the display say "indexing..." ...
I totally accept that technology must move on, and just like Windows XP, there is no supported upgrade path...I listened to some of the 320 MP3's in the Tacoma, and even the wife said they sounded great, so this format conversion process, though tedious, will get me through my remaining time with the Fiesta..