Just a quick note. All went fine. Temps got down to 34 with an occasional breeze. Wasn't cold, in fact I didn't put my hat on or zip up my bag until the middle of the night.
Comfort was good. No sore hips or shoulders like I would have had on the ground.
Gotta run for now-it's Pinewood Derby Day!
Detailed report later today with a photo of my rig.