Picatta - now that's just funny about the pink! Yes, if you'll be running into cooler weather you just may need that sleeping bag!
I wore the pack around with me while I did yard work last Thursday. I put about 4 pounds in it. I just planted, weeded, watered...BUT! It was 90 degrees and 80 percent humidity! Nightmare! But there was a small breeze and I can tell you that saved my butt! The only place that was sweaty when I came in (after about 2 hours) were the hip straps and the area right where the two comfy pads at the top of the sacrum land. I could really feel the breeze blow across my back and it absolutely kept me cool! Way, way, way worth every penny!
Also, just something I tried which worked great for sweat cleaning: put a couple of small drops of tea tree oil on a wet washcloth, rub it together to spread out the oil, then run it over the sweaty areas and let it air dry. Tea tree oil is antibactierial/microbial and smells very fresh. It really cleaned the pack very well! I will take a small bottle with me on the Camino because it's also superb for bug bites, cuts, scratches, bruises. (PS...learned this trick when cleaning my yoga mat as I do Bikram yoga [that's the one that crazy people do in 100 degree heated studios :-D] and it has always cleaned my mat beautifully.)