Recuva found the 2TB+ of files on the crashed NAS. Unfortunately, it would not let me save them to a another drive connected to my PC via the ethernet port. Solution?
Recuva, and most recovery software, require both the source and destination drives to be physical drives attached to the pc (as opposed to network). As your source drive, it sounds, is attached to the pc physically your only real option is to recover to another local drive (for instance your system drive) and then copy them to your NAS.