> I am sure I am not alone in having many directories with a huge
> number of sub-dirs and wanting to work with just one or two. While the
> Shft-Numpad-Minus works great to hide non-essential directories it is an
> error prone pain to apply it to hundreds of sub-folders.
Some ideas:
Have you tried Alt+Z to save the current state? Then you can reload it later.
You could also consider using treespec to jump to the directories involved, and then mark them in the treespec history for quick access next time. Then you could leave them all logged and just jump from dir to dir using treespec shortcuts.
If there's anything unique about the dir names, you could use dir mode and filter the list with a dirspec, although that could involve constant switching between file and dir mode.