Our last coop was a large walk-in frame with little house on stilts inside of it. We needed something movable this time around, so I wanted to go with a tractor type design. I decided to do run below with a nesting/roosting house up above. The coop is accessible from the run via a ramp attached to a door flap in the bottom of the coop. At night, I pull the ramp up with a wire and it closes the door, protecting from cold and predators.
There are two front doors, both open. One doorway is covered with wire, so I can leave it open on nice days, allowing for air circulation and sunshine while the ladies are roosting in their coop. The left door has no barrier when open allowing for cleaning and egg collecting ( it has a hook and eye closure allowing it to be locked when the right door is open.)
The coop part was made with 1/4 inch plywood and 11/2 by 2 lumber for framing, so it's pretty light. It's 3x2 feet on the floor, and the roof goes from 3 to 2 feet.
I'm lucky enough to have a friend who works at a lumber yard, so not only did I get the cast-off lumber for free, but the run was made out of really light mock screen doors that were being thrown away from the same place. We just removed the screen and replaced it with chicken wire, nailed them together, and we had a perfect run.
Because of the friend at the lumber yard, I only had to buy hardware, paint, and nails/staples. All-told this was about 7 hours of family fun, and we spent under $100 to get it done. Such a blast!