The best time to hike through the GSMNP is in December!! You will have the trail basically to yourself. The shelters will be empty, unless they are booked by invisible people. lol. This December I hiked from Fontana Dam to NewFound Gap and saw a total of about 10 people. I stayed in Mollies Ridge, Derrek Knob, and Mt. Collins. Those 3 shelters were empty, along with the Fontana Dam shelter. Whats strange is that when i made my reservations, i was told that Derrek Knob was full. When we arrived at Derrek Knob at 930pm, no one was there and i wasn't about to continue on to silers bald shelter that i had reservations for. All in all, it was a great hike. I can't wait to return from Afghanistan and hike some more.