Years ago, I hiked about 13 miles down the Grand Canyon’s Bright Angel Trail to Plateau Point and back. (This is not all the way down to the river; many people recommend you don’t attempt to hike to the river and back in one day, and I’m part of this crowd.) It took about 8 hours, including breaks and lunch in the Canyon, and my legs were sore for days afterward. But the views I was able to capture were worth it.
Be sure to bring plenty of water and food for the hike! Also, I wouldn’t set my bag down unattended again, as an aggressive squirrel tried to tear into my backpack to get to a protein bar I had inside. I would also recommend good hiking shoes and socks, as well as sunscreen!