I have my wife and I pretty much set up for winter, so I have been working on a setup for my 3 yr old daughter's HH Cub Zip.
For top insulation, I have the military modular sleep system in there and for bottom insulation, I have a 3/4 length thermarest pad between the gore-tex bivy and the outer sleeping bag as well as a reflective windshield shade between the hammock and the diy poncho liner I made yesterday.
When I put her in there she said, "I'm as snug as a bug as a rug!" I think she meant "in a rug!" By the way she was in there when I took the picture.
I wonder how low the temps can go before she reaches her comfort limit.
I was happy with the limited capital that went into her setup, as this new hobby of mine has gotten rather expensive! The Cub Zip was free with HH holiday sale (when I bought my wife's Expedition) The poncho liner was $20 shipped off ebay, the shock cord and s-biners were just a few bucks, the windshield shade was $2 from Goodwill, and we already had the sleep system ($60 shipped from amazon) and the thermarest ($25 off craigslist).