This is a 12-mile traverse of the Pacific Crest Trail (PCT) that makes a great warm-up thru-hike for the full PCT, or a nice overnight backpacking trip.
From Stampede Pass, set out on the Pacific Crest Trail heading north, passing through Dandy Pass at two miles, and after another two miles, arrive at Stirrup Lake. This is another great location for a short backpacking trip, if this long traverse is a bit much.
Continuing past Stirrup Lake, it's another two miles to Twilight Lake and Yakima Pass. This small, quiet lake near the North Fork of the Cedar River is a wonderful respite or stopping point for lunch, before you climb up to Mirror and Cottonwood Lakes and the more heavily-trafficked section of the PCT. Many hikers access the trail between Mirror Lake and Windy Pass from the north as a day hike, so prepare yourself to see a few more folks along this section.
If you're a peakbagger, you won't want to miss Silver Peak, just a couple miles before you finish the traverse at Windy Pass. It's a bit of a haul, so allow time for the climb, but the view from the top is absolutely superb.