There is no camping allowed within 1/2 mile of the main road (Smithsonian Butte road).
The Wire Mesa Loop is a fun singletrack with amazing vistas of Zion National Park and it provides a different running experience for the area. Bring plenty of water. Drinking water is not available on the mesa.
The loop was designed to be traveled both ways, and it's really fun in both directions. It feels like a different trail each direction given how varied the terrain is and the differences going up vs. down on it.
There are three signed "Easy/More Difficult" splits along the trail. Be warned the "More Difficult" routes are significantly more difficult than the easy routes. This map follows the easier option on the splits.
There is also a doubletrack road that travels 1.5 miles north from the trailhead that is a great, mellow out-and-back run. It goes to the rim with amazing views in every direction, and intersects the Wire Mesa Loop. Those wanting a more relaxed run can follow this doubletrack and meet the rest of their group for a break at the rim. The doubletrack also makes a great exit point if runners need to make an early exit from the loop.
Google Maps may give you the option of going up from Rockville or from Highway 59 on the Hurricane side. Do not go the Rockville way unless you have a good 4x4 vehicle.
Be aware that the primary users of this trail are mountain bikers and the trail should be respectfully shared between both parties.