Joseph,
Welcome to WAGS.
A long soak in lye should loosen up most of the crud inside that skillet. You might still have a lot of scrubbing to do, but as Russell pointed out, the surface of the skillet was ground, so it might make a good user. That is unless it is badly warped and you have a ceramic cook top stove.
The lye won't do a thing for the rust, but if the rust isn't bad, try scrubbing with a little vinegar after the lye bath. I think you'll be able to get a good layer of seasoning on it.
Good luck!
Jeff