Simpang Renggam is less than an hour from JB, so it makes sense as a lunch stop when driving up north from JB if one were to leave JB before noon.
There are ample eateries in Simpang Renggam, and we chose Restoran Tai Kai Hock (大家福酒楼) since they are quite highly rated on Google. They are basically a Tze Char restaurant and the standard is above average.
Their signature dish is the crispy duck, and indeed it is pretty good. Overall the food is value for money, and well worth stopping over for lunch.