Here is a resource of maps from the series that will help you with the geographical orientation.
Map of the Austrian-Hungarian Empire in 1914 (before WW1)
Map of the Austrian Empire after WW1
Map of Austria: Tyrol
Landeck is the biggest city before Reschen when heading south.
South Tyrol/Alto Adige/Südtirol
Oberer Vinschgau Valley (Reschen Valley)
This is the reservoir today. At Graun, in the light blue area on the right shore ("Kirchturm von Altgraun") is where you can see the church tower of St. Katharina today. Note, just to the north, that Katharina Thaler's hamlet of Arlund is now located above the lake. Just to the south of Graun, is where the Karlinbach spills into the lake.
Here, as I zoom out, you can also see the landscape to the east. These are the mountains that Katharina Thaler would be living in, where the Vorsäß and the summer pastures are.
Grauner Berg is the area which I use to describe the summer pastures, and, in The Smuggler of Reschen Pass, the area that Fritz haunts.
Nauders, to the north of the pass and now on the Austrian side, used to be the district's legal seat. This was all moved to Bolzano/Bozen after the annexation.
Bozen/Bolzano interactive city map (here you can find the streets Angelo traverses)
List of Characters
Two Cultures, Three Languages, One Big Conflict: How I wrote the series