Distance: 13 miles (21 km) one way
Elevation at trailhead: 4,400 feet (1,340 meters) at the Tunnel View; 7,200 feet (2,200 meters) at Glacier Point
Elevation Gain: 3,700 feet (1,130 meters) including Sentinel Dome; 3,400 feet (1,030 meters) without it
The leftmost green segment marks the trail section from the Tunnel View to Stanford Point, passing the pink balloon, otherwise known as Inspiration Point, along the way. This section climbs more than 2,000 feet (unless you are a smart hiker, in which case you'll be hiking in the other direction and it will descend more than 2,000 feet instead). If you zoom in, you'll notice lots of switchbacks in this area.
The red segment marks the Dewey Point trail, which coincides with the Pohono Trail for a few miles. If thirteen miles doesn't satisfy your workout jones, detour south for a mile at the red/green intersection to see McGurk Meadow. If you're completely knackered by this juncture, your easiest route back to a road will be a mostly flat two-mile trek along the red line south to the Glacier Point Road, at which point you can address the problem of not having a car there.
The next green segment marks the remainder of the Pohono Trail, all the way to Glacier Point. The green balloon marks the spot where the trail crosses Bridalveil Creek; the two miles of trail from here to Taft Point (the purple balloon) climb about a thousand feet - though once again, if you're a smart hiker, this section will fall a thousand feet instead.
The cyan balloon marks Sentinel Dome. The Pohono Trail goes past the base of Sentinel Dome, but doesn't actually climb it. If you're hiking east-to-west you'll be near the start of your hike and you probably won't mind the extra 300-foot climb for the views from the dome. If you're hiking the other direction, you'll probably be hallucinating too much by this point to notice the turnoff.