For many years, I used a short (48") Thermarest and put my internal frame pack under my legs; this worked really, really well with the Granite Gear Vapor Trail pad, with its inch-thick foam backpad.

However, when I went from the Thermarest to the NeoAir (which I really liked, especially the All-Season), the pack was enough thinner than the pad that my lower legs bent uncomfortably (I'm a side sleeper.) So, I went to the 66" pad. My feet-to-shoulders were on the pad; I put my pack at the head of the pad (for some height) and my pillow on top of them. The bonus was that it neatly stored my pack in the limited space of my one-person tent.

Eventually, I switched to the Big Agnes Q-Core and Q-Core SL pads, which I really love. They're much more comfortable than the NeoAirs. The next thing that happened was that I bought a two-person tent that was half a pound lighter than the one-person tent I had been using - giving me the luxury of extra space. I've now upgraded to the full-length (72") version of the pad, and put my pillow on the top portion of the pad. Did I ever miss that extra length before? No. It's just one of the little luxuries I stumbled across when doing the ongoing balancing act of weight, comfort, convenience, and cost.