If you look closely (click for larger image) you can see the trail that runs from Indian Garden to Plateau Point and, yes, the trail ends at the cliff and there is no access to the river. If you want to go down to the river, you have to hike on the Bright Angel Trail from Indian Garden. By the way, Indian Garden is visible from many spots on the Rim and it is deceptively near. Indian Garden, which is not visible in this photo, is 4.6 miles down the trail from the Rim. It is 12.4 miles from the Rim down to the river on the Bright Angel Trail. It is 2.4 miles from Indian Garden to Plateau Point, one way. A round trip hike to the end of the trail you can see in the picture is 19.6 miles, but you have to remember that the hike back is all uphill.