According to this article by The American Southwest, "Early in the 20th century the Hermit Trail was a well used and well maintained route, an upgrade of an old Indian path, used to take visitors to a resort-like campground (operated by the Santa Fe Railroad) beside Hermit Creek, but is much degraded due to decades of neglect after the camp closed in 1930."

Though an out and back to the Colorado River is attainable, the same article by The American Southwest notes two landmarks along the trail that many turn around at. The first, Santa Maria Spring, is just 2 miles from the trailhead and offers visitors drinking water and a shaded spot to take a break. For those heading further down the trail, stock up here as this is the last dependable water source.

The other landmark, Breezy Point, is 1 mile further (3 from the trailhead) and offers sweeping views atop a prominent vista. Should you continue further, you'll quickly be greeted with one of the steepest sections on the Hermit Trail, Cathedral Stairs. Beyond this, the trails sees few visitors, often only backpackers planning to stay at a campground near the river.

Many would consider this run best in spring, the snow and ice melt offering plenty of drinking water along the way. Trekking poles are highly recommended and a hydration vest is necessary for anyone heading beyond Cathedral Stairs.

Sources: https://www.americansouthwest.net/arizona/grandcanyon/hermit-trail.html