The metal actually is better than you would think from the original photos. A lot of what initially appeared to be rust ended up being a layer of peat concreted around the metal. And I opted to clean it up chemically instead of mechanically, that way I didn't remove too much material. I didn't want to prevent it from being restored to new condition in the future by a professional.
There is shallow surface pitting on the exterior of the reciever, sideplates and expecially on the barrel. However, all the engraving and stampings are all fully legible and the sharp edges are still quite sharp. Unfortunately, I did wreck the end of the magazine tube removing it, so it is a new manufacture replacement for now until I track down an original. The barrel also has some pitting, which will definitely affect accuracy and is one of the things I want a gunsmith to judge for safety. Internally it is in exceptional shape, and I don't think any material was lost at all. No pitting, and the original tooling marks are still there from back in New Haven!
And the action, man it just feels like a Winchester should. You can feel the mainspring hasn't lost strength, the shell riser snaps up nice and sharply, and the trigger is one of the best I have seen on an original lever winchester. Judging by the lack of wear on the firing pin, hammer, and trigger sear I honestly don't think it was used very much before being lost.
All the major parts are original still, all I had to replace was a pair of screws, the already mentioned magazine tube, and one roll-pin. The pin and magazine I am already planning on tracking down original replacements, the screws I was able to get originals already.