Blair Lake Trail is a one trailhead wilderness trail, so in and out is the way to backcountry trek it normally. Blair Lake Trail is 13.4 miles long; it's longer than many backpacking trails. The backpacking trail stays roughly within the same elevation zone the whole time, so you get pretty much the same conditions along the whole backpacking trail. This trek should take you about 2 days, so it's an excellent thing if your backpack is big enough to do the job. This wilderness trail has a total elevation difference of 960 feet which is a lower than average number. This is a wilderness trail that is quite long, so make sure you bring plenty of supplies. At parts of the year this vicinity sees very little rain, so make sure you check current conditions and fire restrictions with local forest authorities before you head out.