OMG – this is the longest hike I have ever been on and in addition to that the steepest by far. When I looks across the mountain tops I still couldn't believe that in six miles (plus) I would climb down and back up to the Mt. Sizer peak, it seem impossible especially after the warning from the nice person at the visitor center told us NOT to come back down the 1500 ft 1 mile treacherous road – however time being against us we navigated this road not once but twice… went up it and back down (we weren't sure that adding 3 miles to the hike to make the “loop” would be attainable in daylight). We left headquarters around 9 am and peaked Mt. Sizer at 1 PM had lunch and headed back down around 1:30 – 2 ish, and made it back down to headquarters at 6 PM (even saw the “monument” which was a good oops – we thought the trail marker said Monument Trail… but it was the actual monument.) The rough 1 mile 1500 ft incline (22%) was difficult but luckily the ground was moist so we didn't slip as much as you would if the road had been dry… All around beauty… I have really grown to appreciate flats…. this trail had few but I wanted to kiss the ground every time I came upon the flats. Wondered if we could drink water out of the piped “spring” didn't try.