You may find that used shipping crates are cheap and easy to find where you are, especially since you're in a coast state. Add legs, put a hinge and latch on one side for access, a ramp and pop-door, some vents, paint the outside and clad the roof. The crates that motorcycles come in seem like a really great size.
My chickens are weirdly fond of those plastic nest-boxes that just hang on a wall. With those and the crate-style building (with the frame on the outside) it'd be very easy to sanitize or de-mite, compared to other wooden coops.