No special access issues
Once in the small town of Pietransieri, park your car there (in case you have any). Being in the town square, head west toward the wood on the hillside. Follow the only one road (a quite steep one) leading to the wood for about 500 meters, once you come to a fork in the road take to the left and go ahead till you get to the Majella's National Park N1 trail sign, then go on following the trail: all of the boulders as well as the crag are located along the trail. Walk on past the N1 sign about 50 meters, then you will find the hotspot called Nanoblocs on your left, in the wood. You go on about 100 meters more and you will see the crag, the big boulder called La Grotta is located just beneath.
The whole area is part of the Majella's National Park, so please keep to Park's rules and regulations while climbing or hiking there.
Have fun!