I'm still trying to figure out what kind of enclosure my cat would accept for a heated space, anything too small and he just rejects it, which makes it tricky because in a heated space size and temperature are opposed. Eventually I gave up on enclosures and right now I just have a big heated dog bed on a shelf, which seems to be an acceptable compromise.
With my barn cat he disappears for weeks on end during the summer and is almsot never in the barn during the day.
I keep an open tub full of cat food set out (yes I know of one stray who steals from me), during the winter it gets re-filled twice a month, during the summer it practically doesn't get touched.
Compared to most cats I presume the barn cat is more of the "world traveller" type. The biggest worry is coyotes, but thus far he hasn't disappeared perminently yet so it'll be a few years before the wildlife catch him off guard (probably 50% of the cats around here eventually just "disappear").
https://m.youtube.com/watch?v=-0n2kxkdJgM