I dug a little into Nebraska history, and discovered that the Trutnas were devout protestants. That would explain why I couldn't find them in the Roman Catholic records for Gersov.http://www.unl.edu/czechheritage/churches.pdf
A couple who appear to be your grandmother's grandparents are buried in a Presbyterian cemetery near Wahoo:http://www.rootsweb.ancestry.com/~nesaunde/cemetery/czpresby...
So the next question is, does anyone know where Evangelical Brethren records for Gersov are located? Have they been digitized? Or are they still located in a parsonage somewhere?
An interesting bit of trivia: your grandmother does not show up in the 1920 census because it was taken on January 5-6 of 1920! What in the world was anyone doing in Minnesota in January, walking around taking a census?