For your information: There must be something like 15 Olstad farms in the Gudbrandsdal (valley) and its side valleys. You find them in Østre (Eastern) Gausdal, Vestre (Western) Gausdal, Nord(North)-Fron, Sør(South)-Fron, Øyer and Sel; and there are at least two or three Olstad farms each place, named Nordre (Northern) or Søndre (Southern) or Øvre (Upper) or Nedre (Down) or Midtre (in-the-middle) or whatever. There are also Olstad farms other places in Norway, but the majority are in the Gudbrandsdal area. A lot of Olstad people from all over the country emigrated to the US.
Best wishes, Lisa Olstad, Trondheim, Norway (descending from one of the Øyer farms)
PS: I wouldn't say Vinstra is a city, it's more like a village in a farmhood area.