The danger of this hike isn't in the trail itself, but in the lake of water and the heat that many hikers come ill-prepared to face!
In fact, so many people have encountered serious trouble on this trail from dehydration and heat exhaustion, that the park service has a division dedicated to rescuing hikers along the trail. Of all things, it’s usually the heat that gets people because they don’t anticipate how hot it will be at the bottom of the canyon. Without enough water they usually don’t make it back.
Don't let that scare you, though! It only takes a bit of planning, and this can be a very successful hike! If you have never hiked the grant canyon, this 9.5 mile hike is a great way to make it along and to the Colorado River in the canyon's bottom.
Since the views from the South Kaibab trail are unbeatable, it is best to start from the South Kaibab, hike down to the Bright Angel campground, and back up the Bright Angel trail. This way you get a change of scenery and can hike up where there is more available water.
The real danger here, like I mentioned, is heat! You might not realize how dry the air is, or how much you're sweating since there is shade on this trail, so you can very rapidly put yourself in a dangerous position. Do not attempt this trail in one day! It might seem possible, but this needs to be a 2-3 day hike so that you can properly space it out and keep yourself healthy and hydrated!
On the way down the South K. trail, don't miss the Ooh-Ahh point! This point is named that for a simple reason: because it will make you say ooohhh and ahhhh! Especially if you are around here for sunrise, when the red rock is almost surreal. It is about 1 mile from the top, and a popular turnaround for those looking for just a taste of the canyon. See the pics to see what you might experience!
To make the journey from South K. to the Bright Angle Trail, which I highly recommend, you will encounter some amazing sights:
1) South Kaibab Trailhead - leave here very early to make sure you make it to the Bright Angel campground by the time the midday heat starts to take its toll (11am-3pm).
2) Ohh Ahh Point
3) Cedar Ridge - Bathroom is available here; you have great views from this ridge!
4) Skeleton Point - Don't go farther than this if you just want to try a day hike!
5) Kaibab Suspension Bridge - You're almost to the trailhead!
6) Bright Angel Campground - you've made it!
From here, you can follow a typical Bright Angel Trail plan, and you'll have a great time! Just remember to ALWAYS rest a lot, and ALWAYS fill up enough water at the refill spots!