Ahem, this is one of MY projects......

The house will be insulated, and I'll have a clear flap on the door, so I am thinking along the same design you are. There will be about an 8" high landing below the opening. Tried cedar shavings before, messy, so instead we'll use a padded raised bed covered with carpet. This lasts a long time, maybe I'll have to replace carpet once a year. A small ceramic heater will provide heat if it is really cold. Building a metal housing for that.

Prevailing winds are SW, door is on the N, and the house provides a pretty good wind and sun break. There will be hot direct sun for a few hours of the day, so he can escape that under the dog house. 100+ft tall treeline to the south, and the house is 50 feet away and maybe 30 feet tall, essentially to the SW. The run sits in a line of 20' trees.

He gets a flea pill monthly, so fleas shouldn't be an issue. Fleas started croaking after 30 minutes when he took his first one.

The only thing I may add after getting the roof installed is some sort of wind/sun break on the west side (side you are looking at).

Thanks for the offer, but I already had my plans approved by an engineer, and the City.