Overview: This description will start and end at the junction of the East Rim Trail and Deertrap Mountain trail, close to Stave Springs. Difficult and statistics to the left reflect this portion. Most will reach this point via the East Rim TH off highway 9, though there are other options.
Hike: Get on the Deertrap Mountain Trail and proceed south. You will pass a small cascade on the left, likely the only water you will find on your entire hike. Soon you will emerge onto a fairly flat plateau. Unfortunately it appears the entire area was burned in a wildfire approximately 15 years ago, so there will be little shade the rest of your hike.
After 1.2 miles you will reach the intersection with Cable Mountain Trail. Turn right and hike up and then down to the lookout at the end of cable mountain. At the end is the historic cable tower that served as the upper platform for an assembly used to ferry lumber down to Zion canyon below. The early mormon settlers needed this lumber from the rim, rather than hauling it in from forests in northern Arizona.
Over the edge is a 2500 sheer drop or so to the river, give it a peek!
Head back to Deertrap Mtn Trail and turn southwest. Follow this trail 2.7 miles until it ends at an overlook of Zion Canyon. Towards the end you rack up the AEG as you have to go over several hills (remember, you will pass them going back too!). This trail was sandy and more overgrown when I hiked it in 2010 than the others.
Admire the view from Deertrap Mountain and retrace your steps back Deertrap Mtn Trail the East Rim Trail.
Water: Stave Springs appears to be the only source in the area, or slightly upstream of the spring along the very beginning of Deertrap Mountain trail.
Camping: Possible with a permit from Zion NP.
WARNING! Hiking and outdoor related sports can be dangerous. Be responsible and prepare for the trip. Study the area you are entering and plan accordingly. Dress for the current and unexpected weather changes. Take plenty of water. Never go alone. Make an itinerary with your plan(s), route(s), destination(s) and expected return time. Give your itinerary to trusted family and/or friends.