What is the best itinerary for a first Bright Angel Campground permit: which trail down and which trail up?

Descend South Kaibab, ascend Bright Angel; the loop has a right direction and this is it. The logic comes down to water and exposure.

South Kaibab is the steeper, shorter way down, dropping 4,860 feet in about 6.3 miles along an exposed ridgeline with no water anywhere on the trail. As a descent route it is spectacular: the ridge walks you through open panoramas at Ooh Aah Point and Skeleton Point, with the Colorado River appearing far below by mile three. As an ascent in the wrong conditions, that same waterless exposure is exactly what you do not want.

Bright Angel is the forgiving climb out: water and shade at intervals, most importantly the oasis at Havasupai Gardens with year-round water about 4.8 miles from the top, plus Three-Mile Resthouse above it. Climbing several thousand feet out of the canyon is far safer on the trail where you can refill and rest in shade.

Itinerary shape for a first trip: descend South Kaibab in the cool early morning to Bright Angel Campground at the bottom, roughly 7 miles. Spend your full day at the river, Phantom Ranch, and the creek. Climb out via Bright Angel starting at dawn, breaking the ascent at Havasupai Gardens. Many parties add a second night there to split the climb, which turns a hard day into two pleasant ones.

Two mechanical notes: yield to mule trains, and start every hiking day at first light regardless of season; the canyon rewards early risers and punishes everyone else.