- drive down for how many km's do you think until I see the 'Din Daeng' turn off?
Don't take the left expressway fork towards the airport / Rama IX, keep going straight to Din Daeng. The expressway ends there, which is where you keep in the right lane to enter the tollway.
- Then you say once off the tollway? What does that mean. How long do I stay on that road? Highway 2?
When the tollway ends, merge onto the highway on the right, which is the main one to all points North and Northeast of Bangkok.
When it splits on the outskirts of Bangkok to the left to go to Nakhon Sawan, keep going straight to Saraburi.
At Saraburi, stay on it. You'll go over an overpass that turns to the right. It then becomes Highway 2. Stay on it and you'll eventually get to Korat.
Basically, if you stay in the right hand lane from the time you enter the expressway, you'll get there.