Zion National Park
The Zion Narrows
The Top Down hike starts at Chamberlain Ranch. It allows you to see the canyon walls form before reaching the prettiest and busiest section, "Wall Street" (16 miles one way downstream, 1500ft gradual elevation loss)
Wading in the river itself is necessary in tighter portions of the canyon and the water is usually ankle to knee deep. One unavoidable section was neck deep in the September week I visited.
The riverbed is uneven, good footwear can be rented at a shop like the Zion Adventure Company in town. Wetsuits as a general rule should be worn when the water temperature is less than 55. I was comfortable with shorts and a long sleeve polyester shirt in September for the "Top Down" hike when the water temperature was 60, although extra layers would be good for the early morning start at Chamberlain's Ranch (higher elevation).
It is possible to do the Top Down hike as a short backpack trip, with one night at a campsite along the river. Avoid hiking when there is a chance of rain, videos of flash floods can viewed on youtube for education.
The Zion Subway
A popular photography destination that can be reached on the upstream hike (6.5 miles return, 600ft). The downstream Subway hike is more technical, requiring ropes and swimming.
Trailhead: Left Fork Trailhead to Left Fork North Creek to The Subway, permit required even for the non-technical upstream hike
Angel's Landing Trail
Chains and carved steps help with exposed sections and provide protection from the cliffs on both sides (5 miles return, 1500ft from Grotto Shuttle stop).
Canyon Overlook Trail
Trailhead: First parking lot on right after passing through the Zion-Mt Carmel Tunnel from the main Zion Canyon
The trail offers an elevated view of the canyon without a strenuous hike, but the main draw here was exploring up the sandstone to the right (near the end of the trail). There are unique rock formations at the top and 360 degree views of the area.