I know I can export individual mp3s from one long recording.
However, is it possible to keep one long album recording with individual tracks somehow marked within it? Or even to list them within that long recording (I use mp3tag)?
Or do I have to have each album track saved as an individual mp3?
i.e. can an mp3 be marked for easy navigation to a particular point?
There is no standard way to do that, so even if Audacity allowed you to do that, most programs would be unable to recognise the “navigation points”.
iTunes supports adding “chapters” (for example used in some audiobooks).
If you tag the songs with the track number, you can configure your player software to play the songs in- sequence. And, you can skip forward to the next song or backward to the previous song.
Another solution is to export the songs as separate files into the same folder, then add the folder to the “playlist” in your player.
iTunes support for chapter marks is only for AAC (M4A/M4B/MP4) files, as I understand it. AAC chapter support is official. MP3 chapter support is unofficial, hence most players ignore it.