No special access issues
The easiest way to reach the shore is to park in the free road side Parco della Lesa parking. From there head towards the river following a path in the field. You will reach the river shore but you still high so walk to right following the gravel path until you will see a path to the left with a big opening in the vegetation. From there walk straight and you will arrive on top of the boulder. There is a sandy place so you will know you reached the destination.