This is not a small area.

It encompasses thousands of square miles of rolling prairie, creek drainages, badlands formations, and the pine-covered hills of the Nebraska Panhandle.

The specific terrain varies considerably across this range: some areas are flat and open, others are broken and concealing.

Searching this country for a century-old burial without knowing where to look would require either exceptional luck or extremely specific location information.

The absence of confirmed physical evidence after nearly 150 years of interest in the question reflects the scale of the search area and the specificity of location information that would be required to find the site.