This description is from Toulomne Meadows to Happy Isles
, as I prefer a 6,700 foot drop with a 2,000 foot climb to the opposite.
This trail starts in Toulomne Meadows. If you want to cut a little distance off the run, and avoid some of the chaos of the area, you can start at Cathedral Lakes TH. This first stretch of trail is a gentle uphill through the forest. The path is wide and there are bound to be plenty of people on their way to or from Cathedral Lakes (usually Lower Cathedral Lake
About 2.5 miles from the Cathedral Lakes TH the trail to Lower Cathedral Lake
splits off to the right. It is a worthy side trip and particularly worth adding those miles when you've shaved the miles starting at the Cathedral Lakes TH. The lake can be busy but offers a lovely alpine lake in a short distance. If you don't want to add the mileage however, I don't think you are missing much. Upper Cathedral Lakes is just up the trail, and viewable from the trail, and it is almost as scenic and without the crowds.
Once past the lakes, you'll mostly only see backpackers. Though we saw enough people to remind us we weren't alone, we only ran into a few people or groups until we got to the falls at the top of the valley.
Anyway, past the lakes you'll begin another gentle climb through woods with Cathedral Peak providing the main backdrop. About 5 miles after the Cathedral Lakes TH you'll reach a ridge and drop into a meadow. Crossing it you'll find a trail to Sunrise High Sierra Campsite
and the Sunrise Lakes Trail
to the right, with a backcountry bathroom in case you feel the need. From this point the trail begins to climb again, gently, for about 1.5 miles to the high point of this run. This is where the downhill splendor begins.
Enjoy the views of the mountains in the distance as you drop down a rocky series of moderately steep switchbacks through the forest, quickly meeting up with a stream. It doesn't take long for the trail to begin to moderate and for a soft singletrack to wind its way before you. Absolutely effortless running. After maybe 3-4 miles of this you'll reach a burn area. This doesn't start out badly and there is a lovely creek to stop at for water or relaxing. However, once you move on past the creek, with half dome coming into view and the valley around the corner, the thorny overgrowth does get annoying. It doesn't last too long. Maybe a mile. Then, it is blissful running to the falls. Enjoy the views. Ignore the crowds. Three miles to go.