I decided to give this mat a try. Looking at the thickness, R-value, packed size & weight, and reviews, we'll see how well it performs.
ust Fillmatic Sleeping Mat | REI Co-op
Self-inflating in a matter of seconds, the Universal Survival Technologies Fillmatic sleeping mat lets you rest soundly wherever you go with 4 in. of comfy open-cell foam cushioning.
www.rei.com