I know of an alternative way to Chek Jawa, it is a dirt track
with barrier at the main road. See the map before, it leads to Chek
Jawa, but the sign post on the barrier indicate private area ahead.
I haven't try them, for fear of losing my way (it's 4 to 5 km from
the main road to Chek Jawa). The dirt track is at the junction of
Jln Sam Heng and Jln Mamam.