Note that Peñasieta, AND the albergue, are not on the camino. Signs point the way, and see the albergue notes on how to get a hold of the keys.
From Peñasieta, the climb begins. The preferred, and much more beautiful, route is along the trail so if you spent the night in Peñasieta avoid the temptation of following the road (even though it will get you there).
The elevation gain is about 800 meter up to the Alto de Palo, with a few particularly steep sections along the way.
Here are some marks (from Peñasieta):
2.3 km : Cluster of houses
4.3 km : Intersection with AS14. Do Not follow road, instead keep climbing up a stretch of steep switchbacks. It is steep, but find solace in the fact that the road (even though it will get you there) is much longer.
5.4 km : Water trough for animals.