You can definitely have a 2 lane dirt track, and have it dry hard packed like asphalt. Ive seen it, raced on it, and won races using the outside lane to pass. It seems to me most track prep is done superficially. The surface is broken up, smoothed out and then watered on top. This makes for a quick prep and ok starting surface, but it drys quickly and then becomes single lane.
In my opinion, and Im am not a expert, nor have I done any track prep in my short life.........The surface needs to be broken down to the smallest chunks possible, 4-8 inches deep. Water multiple times to soak the entire thickness of the broken ground. Maybe turn it over once or twice and water again. Pack one time, water, and repeat until the surface is packed. Then use a drag to smooth the surface. Water as needed to maintain the surface moisture. Once the moisture is " in" the track, it shouldn't take much water on top to maintain it.