Agreed.
My Little Monitor Coop was done over a long weekend by my DH and his best friend. DH being an experienced amateur builder and his friend being in the construction trades.
The original run took another weekend later with the door being the hardest part to get right.
Cliff or no cliff, you will probably want to enclose your chickens so that predators can't get them. And yes, you DO have predators in town -- raccoons, opossums, stray dogs, stray cats, coyotes, and more are surprisingly common even in dense urban areas.