There are picnic tables and a lovely viewpoint near the Santuário de São Torcato. We visited on a Sunday at 2pm and found it to be empty. The area is shaded by pine trees and it might be possible to stay overnight, although we didn't test this.
This place is lovely and peaceful. It's best to park in the designated area before the religious site, where you'll find numbered stone markers. Please note that the toilets have been closed since April 17, 2022. There is a functioning tap at the church, however, I cannot confirm the quality of the water. The road leading to the location is in good condition, but it is a bit steep.
Great location. We stayed overnight under the trees. There is water available and trash cans. Not much traffic in the evening and at night. One downside is that the place was not clean, with lots of litter on the ground and toilet paper scattered behind each tree and rock.