I scouted the South Trail the night before I summitted Elbert via the north ridge trail.
There is a small stream that crosses the road just prior to the upper trailhead. I had no problems getting my rental Chevy Cruze to that point, but didn't try to cross the stream.
The road was dry and traction wasn't an issue, but you may need 4WD if the road is wet.
The road doesn't have ruts, but has about 11 swales perpendicular to the road to keep water from running down the road. This is why you need a high clearance vehicle; while I did make it over all of them in the Cruze, I bottomed real hard on a couple of them.
Ultimately, my family and I didn't want to deal with a small stream crossing at the beginning of the climb in the dark, so we did the north ridge trail.