I meant the solution to get the full path of a single selected file, combinable in several parts or in whole, but without getting bonkers in-between.
It seems that in theory at least, LyricsLover's solution is the ONLY ONE. Albeit that "preview" line then opens in my external text editor, is NOT visible within Mp3tag for me, so in the end, I don't know how that would really work either (except then getting the path from the external editor: way over the top...).
In Tag&Rename (30$ plus VAT, but that's certainly not the problem here), it's similar: file name available from in-line editing (possible for the file name only), and just some PART of the folder name from the main window's caption (in brackets [ and ] in there, but, as said, only a part of it).
In AudioRanger (AR), any column / cell / cell combination within any given column is copyable in-line (then multi-line in clipboard in case, so fullpath is immediately identifyable by copying 1 cell, then I put it in AHK variable. Similarly, I can copy any combination of cells from any given column into clipboard, from there into an AHK array, and I also can fill a third AHK variable, e.g. with some sub string from any cell, and a fourth one with some other sub string.
Then, I have up to 4 AHK variables: originalpath (incl. filename), newpath (ditto), originalsubstring (which may be the whole file name), newsubstring (which may be a replacement, or an addition: before, after), and then I simply run the respective folder or file rename string within AHK: done (with the necessary dialog in AHK of course, so as to not have to do "blind" renames).
Most or all "real" tag columns / cells in AR ARE editable, which facilitates the retrieval of (original or replace-/add-) sub-strings, otherwise I would have had to TYPE them into my AHK dialog fields, but as said, the rename is then done within the file system, NOT within the AR grid: In there, there will be more and more de-sync to the file system, necessarily: Thus my interest in Mp3tag, etc.
Thus, I have to adapt my AHK file system mass renaming interface to my (extended) use within AR, incl. automatic emptying of all field values not used anymore.
Similar proceeding would have been possible from within Mp3tag if it made current file AND path value available: renaming within file system by AHK, values obtained from within Mp3tag, and if you proceed from row 1 down to the last one, de-sync between grid and file system in-between becomes acceptable. Oh, and in AR, don't do intermediate control-s, since that would create additional files.
Tag tools seem to start from the assumption that meta data from the web is correct, which, for classical music, is far from being true. Thus, "bulk by schema" doesn't help much, the user needing quickly-adaptive (sic!) bulk processing instead; they have to apply their own, interactive macros if they don't want to need "days" for (complete) renames which should take less than 1 minute per CD (=group of similar files): It's not realistic to have to rewrite the schemata every time: You need to use'em with flexible rename data.
(Even multi-rename in Mp3tag would NOT be a problem since you would have your up to 3 variables, with all the other rename data, and then you would select lines 1, 4,7, 9 of your CD, and trigger the rename... but for that, file names, file name sub strings, paths, and path sub strings must be available without having to perform crazy contortions.)