and/or this trip report
where there is some more detailed info about PeaPod use on the same trip. I used my PeaPod without a quilt of any kind, with just the warm, lofty clothing I would have had with me anyway. I did take an extra down vest to help ease my paranoia about not taking a top quilt. I got by OK with one night mid 20s ( dry) and other nights low-mid 30s ( wet/windy).
By closing the pod all of the way, or just leaving a very small breathing hole, or by turning on your side and rotating the pod so that the breathing hole is on the side and tight against your face like a hood, you can get a rather huge boost in warmth. With these techniques, I can really get by at some pretty cold temps even without high loft clothing. Just with good long johns, or at most some fleece. But, this is not for any one who is at all claustrophobic. And even if you are not, it is not exactly the roomiest approach, though adequate for me.
OTOH, my friend thinks the PeaPod combined with a top quilt is the least claustrophobic approach. He used a lowly 55*F model pod, boosted with a 20*F bag/quilt, and a pad down inside the PeaPod. This allowed him to mostly leave the top wide open near the head and shoulders, and still stay very toasty in the mid 20s. He probably could have done very well with just a 30 or 40*F rated top quilt in the pod.