“Grand Canyon National Park encompasses more than 1.2 million acres, the vast majority of which are inaccessible due to the predominance of cliffs and inhospitable to all but plants and animals able to survive in the desert. The Colorado River bisects the canyon; hikers can cross the river only at Phantom Ranch. If you choose to hike from rim to river to rim, you will have to deal with an elevation differential of more than 10,000 feet from start to finish.” Source: Grand.canyon.national-park.com
We found this great video on YouTube. The video provides the details you need to plan a successful hiking trip in the Grand Canyon- including information about specific hiking trails as well as general hiking tips.