26 minutes walk from Blanca's house to the Taxqueña/Tasqueña (spelling differences abound) southern-most Metro station. From Taxqueña, take the Line 2 Metro toward Cuatros Caminos to head north, and Zócalo stop will be around 11 stops to the north. This Airbnb is a casita/mother-in-law suite that is private from Blanca's house (where a female family member sleeps as well), but the street behind the Airbnb is quite noisy.
I woke-up several times early in the morning, from 02:00 to 06:00 various days, because the street behind the Airbnb is a thoroughfare for the neighborhood. The windows and walls are thin, due to the older construction, so just be prepared that this will be the usual noisiness of Mexico, even if it is a 46-minute walk/commute to the Céntro Histórico. I probably would not stay again, mostly due to the long time daily to get to the center, which was bad planning on my part (though I did get lots of exercise).
Blanca is super nice, her family member is quiet, and the dog is small and will befriend you once it barks for a bit. The neighborhood dogs, however, bark quite a bit for many hours a day, along with the drive-by loudspeaker people that sell microwaves and whatnot, as well as loud people playing music while they drive by. If you run out of hot water, just let Blanca know and she'll change the gas cylinder. You will need to heat a pot of water on the gas stove for coffee/tea, which takes a bit longer than a modern electric kettle, but Blanca was nice enough to offer drinking water, some herbal tea bags, and some instant coffee. Fridge was nice, though there was no bottle opener that I could find. Black hair was around the bedroom and bathroom throughout, which got annoying sometimes. A bar of soap was nice, along with handsoap and dish soap, and you can handwash your laundry outside and hang-dry. No air conditioning, though some windows open if you don't mind some bugs visiting. I didn't need heat or AC when I was there in Nov2018, since it was so nice. You'll get a key for your bedroom as well as for the front gate (typical Mexican lock bar to close it). Nearby restaurants and shops are decent!