You could do this bit by tuk tuk and get off at the sharp right turn.
A sandy track carries straight on towards the plateau. Keep going straight on for about four to five kilometres and at the intersection half way along, don't turn left – keep straight and follow the sign to Ban Khong Huang.
The road turns to the right, crosses a bridge and you arrive at a large village. Turn left into the village and follow the path through the village until you arrive at the foot of the plateau – a motorbike can take you most of the way.
The path leading up through woods is reasonably easy to follow will take you a good couple of hours to reach the top so take plenty of water -- the village at the foot sells neither food nor water.
The forest gets lush at the top and there is a great view over the Sekong valley to mountains in the south.