Ran into similar problems thanks to heavy trucks for concrete and building supplies for our new home.
I'm slowly adding to the road as I can afford it, but here's what I did:
I initially had scraped the area bare, then laid geotextile fabric down, followed by loads of post oak gravel. This is gravel up to 1 1/2" mixed with fines - it's used as road base material and compacts well.
After the concrete trucks got through, I discovered I had a 100 ft. stretch of soft spots where the road was a rutted mess. This was due to a couple of problems - the soil below the road was soft due to water being retained as well as the water not really having anywhere to go. The fabric helped immensly, but the trucks still pumped water up into the post oak gravel causing it to get heavily rutted.
My fix is ongoing and is in 2 parts - it has already proven to be effective:
1 - Road Repair.
I used the box blade and scraped down to the fabric through the length of the soft area, making a pile of wet gravel road base material at both ends of the soft area.
I bought a pallet of Portland cement bags from Lowe's ($6/bag, 35 bags) and spread the Portland as a stabilizer right over the fabric area. If I had done the road from scratch all over again, I would mix the Portland into the soil below the fabric, but I didn't want to pull it up this time. The cement was spread out enough to cover the entire road surface with at least an inch. Do not use Sacrete or regular concrete mix - it's the Portland cement by itself that you want, not the sand and aggregate.
I then spread the post oak gravel back over the Portland cement and used the ag tires and box blade to mix the cement and gravel together. The cement immediately started binding the soil fines, using the existing moisture in the gravel. For final grading I also added another load of gravel for surfacing. This was an economical but labor intensive way for me to stabilize the road - the cement mix helps to bind the gravel base as more of a mat and the fabric works to distribute the load. Cost was $210, but a load of cement stabilized sand was going to be over $400.
2. Drainage.
I realized that regardless of how I fixed the road, the area drainage needed to be modified, otherwise I would be forever fighting water problems. Our property has a large county drainage ditch with a culvert, plus a secondary drainage swale right inside the fence line, deep enough that a 12" additional culvert was needed when we first installed the road. However, the center of our property (where the road was) was retaining water. I decided to use the box blade to start scraping a 5 ft wide drainage swale on either side of the road all the way from the house end of the road to the secondary drainage swale at the front. This is only about a 1 ft drop, but that's enough to route the water away from road area. This is a continuing project, but it allows the water to drain from below the road base so that it's not pumped back up by heavy trucks.
Sorry to be so long winded, but my point is that not only do you have to repair and stabilize the road itself, you also have to take care of removing the water from the road area. Otherwise, you will always have rutting and soft spots as a problem.