Along with my sleeping bag, I always carry a dark wool or fleece blanket. The uglier the better. Aside from being extra warmth or a pillow, it's a great prop for disguising my pack as a pile of bum trash. Tarps and trash bags are too reflective, and the dirty blanket seems a bit more offputting to touch then just peeking under a tarp...
Had a big gray shitty looking wool blanket one night camping out in a sketchy ass spot in Bakersfield. Anytime I heard someone walking by, I'd throw it over me, pack and all, along with whatever trash and plant debris had stuck itself to the blanket. No one seemed to notice me there, or at least thought I was weird enough not to fuck with [emoji14]
Probably doesn't sound like the best way to stash a pack, but it's worked fine so far.