My family (my wife, my daughter and 3 grandsons) completed the rim to rim to rim last week. We took the Bright Angel Trail to Bright Angel Campground. Then we hiked to Cottonwood, where we left our camping gear while we hiked up to the North Rim and back to Cottonwood. We returned to the South Rim the same way we came because of the threat of lightning on the South Kaibab Trail.
The hike was fairly uneventful except for the day we hiked from Cottonwood to the North Rim and back. There were a number of rock slides along the North Kaibab Trail during the winter. The slides took out the water line to the North Rim and parts of the North Kaibab Trail. Unfortunately, those rock slides have not really stabilized -- rocks continue to come down.
On our way up, we passed about 20 workers who were working on the trail. As we neared the top, it started raining mixed with some sleet and snow. When we reached the North Rim, the temperature dropped about 30 degrees. It was miserable -- cold and wet. We took a couple of pictures, filled our water bottles and headed back down the trail. Soon we passed all the trail workers who were headed for the top. They informed us that they were pulling out because the rain was causing additional rock slides. They warned us to be alert for falling rocks. As we descended, we heard and saw a lot of rocks falling. Most of them were a distance from the trail, but a few actually hit the trail. Two of my grandsons were hit by small rocks. One was large enough that it knocked his hiking pole out of his hand. The other left a small bruise on my grandson's head. When the rocks were falling, my daughter asked, "What can we do?" My wife replied, "Hike fast and pray." We did both and safely got below the slide area. All of the rock slides were above the Red Wall Bridge.
My advice -- if you are hiking the North Kaibab Trail, do it when it isn't raining or take a hard hat. The rocks will be falling until the area stabilizes.