Currently, the expressway network doesn't go all the way to Kelantan.

For that, need to wait for the completion of Central Spine Road (CSR).

Even if the dual carriageway (not talking about expressway) goes all the way to KB, say the Karak highway to Bentong then add the Central Spine Road, then add the Kuala Krai - KB highway, physical distance is still about 500 km.

500 km if all dual carriageway, assume average automobile speed of 90 km/h...still need 5 hours 30 minutes or so by car.