This is a fantastic trail as long as you are ready for it! Making the trek from Tamarack Campground, to El Cap is a long but enjoyable feat. You'll access this trail by first taking the Big Oak Flat Road trail and branching north. This section of the trail takes you through some beautiful backcountry, fields of flowers and streams with a lot of undulation. The elevation change is not huge, but you are traveling along the ridge so you have a lot of inclines and declines along the way. Take this route with a buddy as it may be the only other person you see all day.
There is very little info about this trail but I can tell you it's gorgeous. This trail has it all with trees, flowers, meadows, and streams. If you want a quiet path that few see, this is one of them. As a routine runner, I was a little surprised that it felt difficult, but you are higher in elevation than the valley so altitude is something to keep in mind. There are streams, but make sure you have water especially depending on the season. Winter can bring snow pack to this area, and the access road to the Tamarack Campground is closed from December-May, limiting the access to the area further.
This path is best taken as a connection path for an ultimately longer journey:
The best recommendation is to start at Tamarack Campground and make your way to El Cap, before then taking the Eagle Peak Trail
to the summit, and continuing on the El Capitan to Upper Yosemite Falls
and turning off onto the Upper Yosemite Falls
which leads down to Camp 4 in the valley. Getting to Tamarack Campground can be tricky. Most of the road is finally paved now, but there are still some big bumps in the road!