Jerantut is some 190km away from Kuala Lumpur. Depending on traffic condition around Kuala Lumpur, which would add up to total hours of your journey, driving to Jerantut from the Gombak Toll would only takes an average of 1 and half hours via the East Coast Highway. It's 45 minutes from Gombak Toll to Temerloh Exit and another 45 minutes to Jerantut Town. But, mind you, it would be a lonely drive once you exit Temerloh Toll to get to Jerantut as there are not many vehicles on the road.
Jerantut, the town is quite small but the main streets are quite organised. You can basically have a complete tour around within a day unless you wish to get to Taman Negara which is link through Jerantut itself. There are a lot of local eateries, so you wont be hungry but should you are not fancy of local dishes, you can find a Domino Pizza outlet within the town, or the KFC.
This would be my third time to Jerantut. Not expecting much, as it is work basically