The start location is parking outside the Monastery of Ayios Ioannis Prodromos Kynegos at the northern most end of Imitos.
The final cache location can be reached by following one of the many trails in and around Athens that is marked with red dots/circles.
You can check your answers for this puzzle on Geochecker.com.
Pyhr 1: guerr + sbhe = 12.
Pyhr 2: nf jryy nf jnyxvat gur genvyf ba Vzvgbf V ybir gb jnyx zl ovanel gerrf.