There is a camping area near the Rocafort castle that can accommodate 3 or 4 campers. It offers some shaded spots and is conveniently located near the town of Rocafort. The castle is currently under restoration. The camping area is outside the boundaries of the Sant Llorenç del Munt i Serra de l'Obac Natural Park, so there should be no issues with staying overnight as long as visitors treat the place with respect.
A peaceful place with beautiful views of Montserrat nearby. We were also lucky enough to meet a professional astronomer who lives there. He showed us an amazing observation through a large telescope and explained many interesting things to us. It was a pleasant surprise!