Brian, as far as rust prevention if it were me I would not worry about trying to prevent any further rust, I would however try to keep it indoors while you work on it and enjoy it.
If you never plan to repair/repaint the exterior then you could coat it with one of those rust prevention chemicals. But if your plans are to repair and repaint the exterior any time soon then I think you will be wasting your money on rust prevention materials.
The photos look great and it looks like a great score and good start for an authentic restoration.
