The I'm-a-tough-guy t-shirt and shorts thing lasts right up until somebody has to admit that they are actually cold, at which point it is too late to get warm no matter what additional freezing cold clothing is put on. The PFD thing is a whole different matter.
Those chipmunks are something else. I've always hung a waterproof stuff sack with food and have never had anybody try to get in, but obviously it would never stand up to the abuse that plastic lid did. But it gives me a thought.
Recently I spotted some no-longer-in use mouse holes along the back patio of my dad's house (trying to sell it). The buggers chewed holes right through the cinder block! I balled up steel wool with caulk, stuck that in the hole, then finished it with caulking. Apparently that works well (dad had birdfeeders forever back there, so I'm sure the mice thought hey, why don't we just chew a little hole or five here, and we can live in comfort with a constant year-round food source fifteen feet away? Sounds like a plan. But it sort of gives me an idea.
Steel wool would be a bad choice for this, but a copper Chore Boy scouring pad, kind of pulled apart and maybe duct-taped to the edge of the lid might do the trick, or if you made something in advance, like a halo with the copper chore boy secured to it that could be placed on the lid when you store it would work. I don't know what else to suggest. Maybe food barrel makers should start infusing little metal strands of steel wool right into their plastic lids to annoy would-be chewers....uh-huh.
That amount of chewing and damage is just astounding. That took quite a while to achieve, so that was a pretty determined animal or two.
Well, another thought - battery operated stobe/motion light on top of the barrel. That wouldn't be annoying. I had a mouse that wanted in our tent a couple of years ago, it wouldn't leave and I couldn't figure out why because I keep a very food-free tent. I positioned a flashlight at the tent door, pointed away from the tent and that was it for the mouse that night. (The next day I discovered a granola bar wrapper in a jacket pocket. That's all it took to attract the mouse.)
Terrific report, really enjoyed it. Really like the photo of the moon!