What strikes you from the relief maps and photos in the museum is that the front lines were high up in the mountains. It seems inconceivable that troops could fight at these altitudes, particularly in winter. There is a long distance walking path that follows the old trench lines, for the very hardy enthusiast!
We finished the day off at the Austro-Hungarian fortress of Kluze. Built in 1882, on the site of earlier castles, it dominates the pass between Bovec and Tarvisio in Italy. There is a museum inside the fortress which is well worth a look.
If you have time there is another fortress at the other end of the front lines at Tolmin.