The hike on Caribou Lake Trail starts out steep and never really mellows out. From Big Flat you cross the South Fork of the Salmon River and start up the switch backs. After five miles or so you come to a usually unmarked trail junction, in a small meadow. Follow the old trail down the hill one hundred yards or so if you need to get water. The easiest way to the lake is along the new trail. This route wraps ten miles around Caribou Mt. through Browns Meadow giving hikers more opportunities to get water. The old trail continues to switchback up the mountain to 8,000 ft the highest trail in the Trinity Alps.
From Big Flat you would have gained over 4,000ft in just over five miles. It may be the hard way but it's also the best way thanks to the awe inspiring view of the Caribou Lakes and Sawtooth Mountain.
The first lake you arrive at is Snowslide Lake, this one has the best camping with warm water, shade, and even a little privacy.
Lower Caribou Lake is incased almost entirely in granite. This rock bound lake has only one camp site worth staying at.
The Inlet to Lower Caribou tumbles down glacier carved rock.
Upper Caribou Lakes make a good day hike from Snow Slide Lake, thanks to the sheer size of the basin.
You can easily spend a few days exploring the hidden coves and ponds of the upper lake.
Also, the Caribou Scramble makes a great day hike for views of Morris Meadow, Sawtooth Mt., and the granite gems Emerald and Sapphire.