This is a technically and physically demanding trail which can be done as a loop or an out and back. Those willing to take great risk can try their skills on the famous Portal Trail singletrack descent to finish the loop. Warning! The Portal Trail has some "really extreme" exposure and people have paid the ultimate price negotiating certain sections of this trail.Portal Trail is a very narrow singletrack that skirts the face of a near vertical cliff. Many people walk this part of the trail. Poison Spider Mesa is a challenging ride due to the attention required to negotiate loose terrain, babyheads, bedrock ledges, slickrock (lots of slickrock) and at times deep sand all on one of Moab's classic Jeep 4x4 trails. Once on the mesa ,there is much slickrock to play around on. The ride starts with a tough climb on bedrock and the occasional alluvial terrace or deep sand and then on to a flatter ledgy surface. The trail turns curvy a bit then some confusion awaits for finding the route to the slickrock. Once on the hallowed surface you can freeform ride to the mesa or follow the trail markers which are little painted Jeeps. If you choose to make your own way to the mesa, study the trail map first and keep a look out for certain landmarks to help you navagate to the rim. At any point along the trail you can turn around to make it an out and back ride.The mileage count is assuming you follow the painted markers to the top, however, mileage becomes a moot point if you decide to freeform ride once on the slickrock.
From Moab. Go North on HWY 191 from Center and Main St. intersection 4mi. to Potash Road (UT279) Turn left. Continue for 6mi. until you see a sign that reads:"Dinosaur Tracks" -turn right up the hill to the trailhead parking area.
http://www.singletracks.com/item.php?c=1&i=3039