Find a sheltered spot for your hammock far down the slope from the formal group camping area. When you leave the group campfire at the end of the evening, go down the hill to your hammock and fire up your stove to heat some water. Put the water bottle or bladder of choice (proven non-leaking) in your foot box. Then, RUN, up the hill to use the porta-potty (hope there isn't a line; if so, improvise​), then go back down and tuck in for the night. Start out warm, stay warm.