Are you sure you really needed to use the sand paper? I have never seen a case where Simichrome or Mothers and elbow grease or a buffing wheel didn't bring back a mirror like shine.
The pitting was quite severe. The car spent 10 years two blocks from the coast sittin in an uncovered car port. The trim looked like the surface of the moon. I used to have a vintage travel trailer and the sandpaper treatment never failed me when I polished that sucker. I've never actually seen Simichrome. Is it more abrasive than mothers? I will say that now that I've knocked down the rough surface of the initial oxidation I'm sure I won't have to go that route again.
Good idea on the bronze wool. The bumpers / chrome seem to really come alive with once you cut the surface crud.