There is only one trailhead, so you're looking at an in and out backcountry walk. This area does get very dry sometimes, so make sure you check current conditions and fire restrictions with local forest authorities before you head out. Now, this is roughly a 2-day backcountry walk, so better have big a backpack to fit all the stuff you need. The total elevation difference for Blue Lake Trail is 2,356 feet which is an average number. This is a long wilderness hiking trail, so make sure you bring plenty of supplies. Blue Lake Trail is 13.2 miles long; it's a long backcountry trail. This backcountry trail goes through some very different elevations, and that means that some parts of the backcountry trail could be very different from other parts of it.