No special access issues
Drive from Nafplio to Kadia. At the junktion in town (37. 5412328 ; 22. 9814528) you turn left and continue till you see a big Marble factory to your right. Here (37. 5412328 ; 22. 9814528) you turn right and shortly after you stay right on the fork again. Passing the factory you continue this very road and keep your eyes open for the wall to your left. Park either down on the road (37. 32284 ; 22. 58532) and leave enough space for other vehicles to pass or, if your car allows it, go up the dirt road to your left and park there.
The approach is simple. Follow the well marked path starting from the dirtroad backwards left and you'll arrive under the first lines in less than 5 minutes only.