Thanks for all the replies. I should have stated at the outset that this was a donated bike which I am trying to get functioning to re-donate to a homeless organization. The goal is to get the bikes in rideable condition at the lowest cost, so that I can do more bikes. I could put a new chain on this, but it would double the cost on this particular bike so I feel I can invest some labor to keep from spending that money, which will free it up for the next one.
I did measure the chain for wear before I started, and after the derusting.