Distance: 7.4 miles (12 km) round trip;
7.8 miles (12.5 km) round trip for Mono Pass plus the Sardine/Mono Lakes overlook
Trailhead Elevation: 9,700 feet (2,950 meters)
Mono Pass Elevation: 10,599 feet (3,230 meters)
Elevation Gain: 900 feet (275 meters)
The red line shows the Mono Pass trail, from its trailhead in the north, along the Tioga Road, to just above Upper Sardine Lake, a short ways outside the park. Though it's not marked here, the trail continues to Lower Sardine Lake and eventually to Walker Lake, which is 5.2 miles (8.4 km) from Mono Pass. (Mono Pass is right on the Yosemite boundary.) It's possible to drive to Walker Lake and then approach Mono Pass from the east, though it's longer and requires lots of climbing (about 2,600 feet/800 meters). The conventional Mono Pass trail, by contrast, has only 900 feet (275) meters of elevation gain, most of it gradual.
The green line marks the side trail to Spillway Lake. This segment is 1.8 miles (2.9 km) long. There are several additional lakes nearby on the slopes of Mammoth Peak, though there are no trails to them. They are, from top left to bottom right, Kuna Lake, Bingaman Lake, an unnamed lake, another unnamed lake (no doubt the park service would welcome your suggestions), and Helen Lake. The lakes visible to the east of Mt. Dana, near the top right corner of the map, are Kidney and Gibbs Lakes.
The blue line marks the Parker Pass trail. The section outlined here, reaching to the Yosemite boundary, is 1.8 miles (2.9 km) long. However, the trail continues for miles and miles outside Yosemite in the Ansel Adams Wilderness, past Parker and Koip Peaks, beside the Alger Lakes and Gem Lake, and on to a multitude of other points farther south, though you can also veer east and reach a road near June Lake. Parker Pass Lake is visible just south of Parker Pass itself (where the trail leaves off).