I had a similar experience looking for Sarah. I found her in some probate records (as a witness on a will) and went through and identified the family she was staying with. They passed away in 1848, so I identified all of their adult children, and then find each household in the 1850 census before I found her, living with a step-aunt who had married (and changed names) twice. Sarah was going by her middle name, with an incorrectly transcribed surname: Sunsford.

Per another note in this thread, I've found her in the Richmond newspaper "List of Letters" column (identifying names on unclaimed letters still in the post office) for 1859 and 1860, but she doesn't come up in a census search.

Is there a way to specify that I only want to search the Richmond census book for 1860? When I try searching I get all kinds of stuff: Tennessee, Missouri, New York... I can browse the entire Richmond census in the card catalog, but don't see how I can search just that one book.