You must be speaking of my Grandmother's family.My grandmother was Faye (Gebhart) Hofmann, and I know she had a brother named Marvin Gebhart.They lived in Alliance, Nebraska, which is in Box Butte County.
Of course I know the most about my grandmother, but I also know some about the others.For example, Martin was quite renowned as a trout fisherman.I'm told that he never revealed his best fishing spots to anyone.Martin and Dorothea were fond of the Black Hills of South Dakota.There are some stone walls and posts in Alliance that Marin built out of stones Dorothea collected in the Black Hills.
I also know that Marvin was a gunsmith and painter (among other things.)I remember seeing some of the signs he painted.
I'm new to this, so I don't know what the process is here.I assume you want more detailed information?