We decided to hike down the South Kaibab Trail because there is no water on this trail (as opposed to the Bright Angel Trail on which we hiked out), and we figured we would need more water on our way up than on our way down.
The trailheads for the South Kaibab and Bright Angel trails are pretty far apart from each other, so we decided to park our car next to the later one and take the "Backpackers Express" shuttle to the South Kaibab trailhead located near Yaki Point. The South Kaibab Trail is 6.3 miles (10.1 km) long. Over this distance it drops 4,860 ft (1480 m), which makes it pretty steep. All of us could feel it in our knees when we were making last switchbacks in the Inner Gorge, just before the trail met with the Kaibab Suspension Bridge on which we crossed the Colorado River to get to Phantom Ranch and Bright Angel Campground.
It took as "only" 4 hours to hike all the way down to the bottom of the canyon, more or less as much as we had predicted it would take. So we had thought that after setting the campsite we would still be able to go for at least a short hike, but we ended up being so exhausted that we skipped that plan and spent the remaining of the afternoon relaxing and chilling in the shade.
On the way down the canyon, view to O'Neill Butte (on the left) from Cedar Ridge Point:
The very first glimpse of the Colorado River, just after passing the Tipoff:
The first views of the Bright Angel Creek Oasis:
The Suspension Bridge:
Crossing the Colorado River: