To hike down you have 2 possiblities:
1) same way back - duration 4 hours in total
2) you walk down on the back side of Pirchkogel. You walk over the "Feldringer Almböde" which is a nice and beautiful area. From there you come down to Marlstein and further to Ochsengarten - duration 5,5 - 6 hours.
TIPP: park the car in Ochsengarten and take a bus to Kühtai.
The following parking facilities are available in Ochsengarten: