I made some progress (and I won't tell you how many times I have ripped various sections out!) Let's just put it this way: I had to buy more white Perle Coton.
Didn't get very far on the door mat last night; the eyes were tired and the Ott Light didn't shine enough said light on my canvas for me to see where I was going.
(Yep, I just noticed that the white sections between the right windows are missing.)
Here's a close-up of the windows beside the door. The shimmery effect is created by adding one ply of Bijoux #460 to the gray floss.