This is a great topic, since so many do dayhikes. A SAR guy who works in the Smokies told me that a lot of their SAR missions are for dayhikers since most never expect to be out overnight and don't plan ahead like us survival nuts. Improvised shelter becomes a very important issue for the dayhiker, as opposed to the overnighter who is planning to make some form of shelter.

Like someone else said, it sounds like GoatMan knows his stuff & would be fine with whatever was on hand. I too love the old AMK ThermoLite products. I will say that the AMK HeatSheet and bivvy are truly more durable than the old-school mylar space blankets & bivvys based on my personal tests. Doug Ritter has fleshed this out well.

I prefer an oversized orange trash bag over a tube tent. This is a strategy espoused by Peter Kummerfeldt although I think the 4-mil bag he sells is too thick & heavy (over 8oz) for the purpose; a 2 or 3 mil bag is fine. You can use this same technique with the AMK HeatSheet bivvy, making for a very effective package that is light & effective.



I can cut a hole in the corner of the bag and wear it as a piece of body-sized raingear that protects me as well as (if not better than) a tube tent when sitting/laying down. But I can also wear it while hiking if need be; just add a couple of arm holes. I always hike with a lightweight waterproof/breathable shell (Patagonia RainShadow) but I can give the bag away to someone who gets caught without raingear, or I can slice it up to make a sheet/tarp/whatever.