I laid all the parts out in the garage and then sanded each piece and put two coats of water based polyurethane on the wooden pieces. At some point it had been painted red and I left as much of that old paint as possible. I was able to preserve some scratches and doodle marks as well. Unfortunately, there were no initials or carved hearts. I spray painted the cast iron parts with black Krylon.
It was rather tricky getting all the pieces back together; the slats fit together like pieces of a puzzle and one piece seemed to be missing.
But, I persevered (and jury-rigged it a bit) and am very happy with the result.
It now resides in a corner of our guest room - a nice spot to sit and tie your shoes.
A little research revealed the desk was made in Indiana by Peabody Stiggleman in 1906.