At about the 5-6 mile mark (coming from the Sedona end) there is an overhang on creek left. (right side if you are heading upstream). It is about 40' long and right on the creek bank. Just upstream of here, if you climb up a small side "trail" on creek left and keep heading toward the high wall to your right (about 1/8 mile from the creekbed) there is a "cave" of sorts. It is about 30' deep and varies from 6' to 20' wide, with a sandy floor. There is no need to bring a shelter on this hike.... save 3-6#'s.
If the opportunity presents itself, I'd say do this as a one-way/shuttle hike. There are about 3 or 4 short pools to swim and the water is cold, but it's a terrific adventure. The lower section is inundated with people, and there's that pesky Red Rock Pass, as well.
From the top it is about 6 hiking hours to the overhang. From the bottom, about 4-4.5.
There is not much of a "trail" in the upper section, but obviously you can't get lost.