I took my kudu on a 30,000 acre property in S. Africa in Limpopo. I know there is a split between high fence and free-range/low fence hunting on here but I can tell you...It was not easy. I really thought we were going to leave that day empty handed. The property was incredibly thick and we just happened to luck out and have a decent (not a monster), shooter male come to the water at the blind we were at. It's the one in my avatar. We had driven around a ton that day, only would spot them for a second, and most were females and immature males. They do truly disappear in an instant, very quietly. For every, 2-3 immature males and droves of females you see, you might spot one good male.
The real driver is terrain. From what I understand, the Stormberg Mountains offers some unreal free-range kudu hunting in Eastern Cape. The difference between mountain hunting and hunting on the brushier, flat areas is glassing then stalk vs. spot then stalk from the truck.
In the low/plateau/flat lands, like Limpopo, you are not going to glass. It's too thick. Up in the mountains, they literally hunt them like they do elk, sheep, deer, etc here in the USA. Get up to a vantage point, glass around, find what you're looking for, and put a stalk on. You could just luck into one on a walk, driving, etc. They seem to disappear even easier in the mountains with the shifting terrain, elevation, and shadows.
You can definitely try and bag a monster your first time out. However, you may want to get your feet wet with hunting a decent bull somewhere with a little easier terrain.