From Palcamayo, first you need to catch a colectivo taxi up to San Pedro de Cajas (45 minutes). The road follows the river up the valley (past Huagapo Cave) before zig-zagging up to the left away from the river. On arriving at San Pedro, we have to return to this river, which is now the other side of a low hill towards the right on entering San Pedro. From the plaza, leave on the right hand side, heading across the valley towards the low hills there. You'll cross a small stream (shown here in the picture), and then head straight up and over the hill beyond.