/ Let's talk driveway material. Just under 1/2 mile long. #21
Re cycled asphalt would be my choice.
In my area it is even cheaper than crushed stone and has the advantage of re gluing itself under hot sun and then sheds water.
Eliminates the need for annual grading as well.
Same recommendation here. We had crushed originally as the OP had. About 12" deep. After 15 years it needed a little repair and the installer recommended recycled asphalt. I looked at my neighbor who had it done many years ago and had mine done also. Very happy with it, but do it in the summer. It also is cheaper in my area. I think you should contact local people for the best recommendations for your area.