I travelled from JB to Janda Baik over this chinese new year break.
From the Sungai besi Toll follow the Kuantan sign to the Karak Highway. At the sampah Genting RnR turn left into the small road behind the RnR you will see the round about, take the turn into Janda baik.
I went there to look for the mountain streams that runs down from the Genting and Bukit Tinggi area. You can't see the streams they are well hidden behind the private properties. Just look for the place where there are many cars park by the road side, you will find the river. We stayed at the Suria Homes Villa the river is just behind the Hotel. The river is clean,water clear and cool. Not deep but rocky.
You wouldn't get lost in the area, its like a circle. Roads are narrow so drive slowly.