The army cot won't last a week, I fear. It's bulky and heavy, an picking it up once thinking "Meh, this isn't too bad" is a lot different than finding a place to comfortably pack it and lug it with you fucking
everywhere you that go. It'd be awkward to lug it on to public transport, should you decide to spend a few bucks to save yourself from walking across a major city. Where would you put it if a sweet ol' lady in her smartcar decides to stop and pick ya up?
Go with a sleeping bag, and if you're feeling adventurous...get one with a bivvy sack and use the bivvy sack as a shelter. Bivvys are waterproof exterior liners to sleeping bags, and you can use em' in an emergency to escape the elements. Just crawl into it and seal the shit off like a burrito
I slept like a baby with just my old army sleeping bag/bivvy sack in Death Valley at 10 degrees, and south Florida at 80 degrees with a steady tropical downpour
If you go that route...DONT FORGET A SLEEPING PAD. Holy shit, I didn't realize the difference until I traveled with
@Viking_Adventurer and
@kaichulita and got a chance to sleep with some kind of insulation between me and the ground.