If you are traveling from Terengganu to Kota Bharu, it might be worthwhile to divert a little to Besut. Besut is about 15 minutes drive from Jerteh. It is the same route if you are going to Perhentian Island.
Bukit Keluang is actually hills and caves along the seaside. There are a lot of bats inside the caves. Just a short distance walk and you see a resort.
Depending on the water tide, if you are lucky you can walk through one of the caves.
However, you can also walk to the other side of the cave through the bridge.