Best trick ever.
Grabbed the wife's sewing machine and sewed a pocket up the bottom 2/3rd's of the sleeping bag. The Thermarest now slides in there - no more rolling off the mat in the middle of the night.
I also have a chair kit for the Thermarest, cool on it's own, but you can also use the packing straps from that to attach an inflatable pillow firmly to the mat.
The net result is a MUCH better night's sleep, no more rolling off the mat, it's a lot warmer, and the damned pillow doesn't run away all night.
The rest of my kit won't help you, too hot here ;)