One of the things I worried the most about being homeless was surviving the
winter.
A sleeping bag rated for -12 F is comfortable down to around 38 F, then I
started to feel the cold.
I found by putting one of those silver mylar survival
blankets under the sleeping bag and an other one on top with a blanket on top
of that, I was able to sleep in temps of 17 F.
I could feel some cold but it was not
enough to keep me up.
And of course I have my head inside the sleeping bag under the covers. 
I have a thermal sleeping bag inside a one man tent pitched on a roundabout that nobody can see or will find it's finding that perfect pitch.
Write on a bit of card...
'Family kidnapped by ninjas
need $ for karate lessons'
Works a treat. I just try to be hilarious all the time even the wardens laugh at me. Be entertaining without being threatening it goes down great. I pretend to play air guitar & get right in to it sing the notes daa naaa naa da naaaaaa naaa the worse I sound the better it gets I don't have a musical bone in my body people just like a tryer I suppose.