We've had a new friend around here for a few weeks. Started with just quick visits, then he hung around enough that brother could pet him at times.
With the cold weather, I ordered him a "house" (litter box with lid) from Amazon...and fitted it with a thick towel and a fleece blanket. He is not snug, well fed...and totally at home. Yesterday, I put a flea collar on him with no problem...not sure if he was a pet before; as he was a bit wild at the start. But, he has certainly been handled before as he likes to be picked up and get head rubs.
The cat box is a corner model but it also comes in a standard square style. It has a hinged door, which I removed because he was not so "sure" about that. It is turned facing the house on the porch, so doesn't get any direct wind...put when it was really cold this morning; he slept with his hind foot over his ear (at least I think that is why he was laying in that position).