Sheep Lake and Sourdough Gap via Pacific Crest Trail Professional Review and Guide
"The Pacific Crest Trail to Sheep Lake is better known to backpackers than to wildflower enthusiasts, but this stretch of the PCT is gentle, scenic, and only a short distance from Chinook Pass. This trail provides a good introduction to the flowers of Mount Rainier.
Late July through early August is generally the best time to experience the floral displays, but if you hike later in the season you will also find ripening blueberries and plenty of flowers still in bloom. The combination of berries, late summer flowers, meadows, and views of Mount Rainier make this a hike to remember. Sheep Lake is also an ideal destination for beginning backpackers or families with small children. Because the lake is not in Mount Rainier National Park, camping is allowed on a first-come, first-served basis, though solitude may be hard to come by."