Pico Casillas is one of the first peaks on the eastern side of the Sierra de Gredos. Here the Sierra de Gredos is a bit milder in character than in the central part; although we have to overcome 800 meters in altitude, the hike is very easy to do. The Pico Casillas lies beautifully open and therefore gives a nice view on both the central part of the Sierra de Gredos with the Almanzor as well as on the Sierra de Guadarrama on the Madrid side.
- Cross the bridge (1) towards the parking lot at "El Castañar" (2) where we go straight ahead, through a wide path. Further on this path we follow the bend to the left and turn right, onto another wide path (3).
- A little further on we turn right onto a track that diverges from the path (4) and we cross the Era del Corcho. At the other end of the field we encounter a fence of a private property (finca privada), where we turn right (5) onto a path that runs parallel to the fence. This path is regularly marked with milestones.
- Further on we cross a path and go straight on, still parallel to the fence. The path widens and we walk further over the ridge with a beautiful view on both sides.
- We follow the path a long time until eventually, with the Pico Casillas now on our left, it ends at another path (6), where we turn left. This path as it were runs around the Pico Casillas and descends to the peak.
- We arrive at a fence which we go through and then turn left on the path behind it (7). This path keeps ascending and leads us to the Pico Casillas (8).
- From the summit we walk back to the fence (7), go right, descend further and return to the fork where before we arrived from the right (6), and where we now go straight on.
- We now initially ascend a bit, then descend and turn right at the first opportunity (9), onto the PR-AV-21. We keep following the PR-AV-21 and thus at the first fork (10) turn left. We keep following the PR-AV-21 and thus at two successive forks turn right.
- This way we reach a dirt road about where we turn right (11). Through this road we walk back to the bridge where we parked the car (1).