We'll have a more complete update later on, but I think I've found her manifest entry thanks to recently released passenger list indexes at Ancestry.com.
The entry below shows Gesche Fecht (her maiden name) with her apparent son Geerts Weerts listed before her and her apparent daughter Antje Weerts listed after her.
This is from the passenger list for the America, which landed in Baltimore on 10 July 1887.
The names are not quite what are expected for Gesche and Antje, but there's a reason behind the apparent discrepancy and the ages are pretty much spot on.
We'll have an update in a future issue, along with a complete analysis and a citation. Just because it "looks like" I have the correct people does mean that I necessarily do. In this case, it helps that the name is uncommon, but the relatives travelling with her help to seal the deal.
The manifest is the last missing piece in locating Gesche--the rest of the puzzle was explained in issue 15 from year 1 of Casefile Clues, "Finding Gesche's Girls."