I like it and especially with the added run space. The only thing I did'nt see was a door for the coop to secure them at night. My run is not very secure either, the thought is if a dog or larger animal is attacking they'd run into the coop. But I do have a door on the coop to stop the night preditors like Mink coming up from the river.
The first week I put the chickens outside I'd started with one of the kids old plastic houses. Ya know, the 3x3.5 houses kids use. Anyway, I'd not put it on a board as they loved the grass...that's when I learned what weasels can do. Needless to say the tractor was finished the next day and that plastic house put on top. Worked great for the entire summer until I built the permenant 4x4 coop that now sits on the tractor/run.