As I've gotten older, I've gotten progressively more claustrophobic. When I was in my 20s, I could sleep in a tight mummy and a bivy with no problem. Now, any mummy makes me too uncomfortable, and I find myself leaving them unzipped, which defeats the whole purpose of the bag. In my mummy days, I've slept on ice flows and igloos. I have not had the pleasure of cold weather camping since those days - and I always used a mummy back then - so I'm a little out of practice for what non-mummy bag will work best when the temps get below freezing.
I've been looking most recently at the Western Mountaineering Ponderosa MF ( http://www.westernmountaineering.com...s&ContentId=36 ) which is a 15 F bag.
My question is this: How would I fare on a through-hike in something like this? Would the open end pose problems when the temps drop? Do any of you have experience hiking the trail with bags like this?