Dear Mr. Wolfteich,
I think, it is simple:
He was an "Gastw." = Gastwirtschaft or Gasthaus or "Gastwirt". "Gastwirt" is the man who kept an inn. Gasthaus or Gastwirtschaft means in Germany a simple Restaurant of the village, where the people will eat, drink an celebrate s.b's birthday, marriage and other revels. In the last centenaries the people shaked off worry with fríends and family.
"Ortsch." is the shortform of "Ortschaft", it means a village, locality, place, (small) town, unincorporated community or a built-up area.
"Einw." = Einwohner = means (in)habitents. I think, you understand now ...
Best wishes from Germany
Maria Fröse