I also think it's interesting that in early episodes, Edie hollers out the door to Wesley in the shed and he's right there. Later the shed is obviously farther away - a hike down the road, or sometimes she even drives there or sends Barry.
I can't recall the details, but did she consistently drive or send Barry from the front door? If so, and if the shed was on the same side of the terrace as the back door, it could be a bit of a trek from the front because she would have had to go around the end of the terrace and down the road behind it to arrive near her back door (and the shed).
Marianna