There is only one road to the Colorado River within the Grand Canyon, a 20 mile route down the major tributary of
Peach Springs Canyon, starting at Peach Springs along Route 66. The road is unpaved but generally fine for all vehicles, at least as far as the crossing of
Diamond Creek, 2 miles from the river. All of the road is within the
Hualapai Indian Reservation, and a fee of around $30 is required for access. The canyon at this point is not quite as deep or as wide as around the South Rim, but it is still spectacular, and the confluence with Peach Springs Canyon is a wonderful place to explore, and to camp.
Peach Springs Canyon - full description