I like the bivy idea for a truck kit. I went with the Outdoor Research Alpine Bivy Lightweight, breathable and roomy for a low profile shelter. Any good mummy bag will do inside the bivy. You might also consider a good wool blanket for use inside the truck. This packs a little bigger than the AMK gear, but with a full size p/u you aren't exactly hurting for room.
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Better is the Enemy of Good Enough.
Okay, what’s your point??