The walk up the Virgin River into the Zion Narrows is a "must-do" experience. Bring or rent water shoes, and use a hiking stick. My tripod did double-duty as the hiking stick. Keep an eye on the weather. Getting caught in a slot canyon during one of their frequent flash floods might be more excitement than you want.
This stop in Zion National Park was while driving back from teaching a workshop at the Anderson Ranch Arts Center, in Snowmass Village, near Aspen, Colorado. Of the stops I made on that trek, the Narrows and the Indian ruins at Mesa Verde National Park were the highlights.