"...have a serious case of smug going on right now."

A well-deserved one!

I wish you were our neighbor. Each of our three bedrooms upstairs has ONE double outlet. None of them are grounded, so of course none of them have openings for three-prong cords.
Only about half the outlets on the first floor are grounded. The attic has knob-and-tube, but isn't hot for some reason. We're postponing getting an electrician in to do the work until it absolutely has to be done.
A huge pain in the a$$, but it's worth it to live in a house with PLASTER AND LATHE walls.

I would get a pro electrician in to be really sure things are properly done (no reflection on your hard work or obvious knowledge) because if even one tiny thing was missed, one wire mismatched to another. or anything else that you just might not be 100% familiar with, your mother's life could be at risk.

"I would get a pro electrician in to be really sure things are properly done (no reflection on your hard work or obvious knowledge) because if even one tiny thing was missed, one wire mismatched to another. or anything else that you just might not be 100% familiar with, your mother's life could be at risk."

While it IS possible to create a hazard with wiring, it is not nearly as risky as you seem to think.
Most simple circuits are just that, simple.

The overwhelming majority of the time if you make a mistake the circuit either does not work (an open) or trips the breaker instantly (a short).

House wiring is very simple.

If this were anything other than a straight run circuit, starting at the outlet and ending at the electrical panel, I would have gotten an electrician in to inspect my work.

This is the absolute simpliest circuit that can be run, a dedicated line with no branches.

My Dad was a civil engineer and my Grandfather a mechanical engineer. They rewired both the house Mom lives in now (Dad grew up there) and the house that I grew up in, and we did a lot of other wiring projects over the years. Plus a friend of mine is an electrician for Norfolk Southern. His advice to me was "Black to brass, white to silver, ground to green for the outlet, black to breaker, white to neutral, ground to ground in the electrical panel." Or, as he said, even you can do this one.

Dad and I had already laid out the fundamentals of pulling a sub panel into Mom's office before he died last year, so I had absolute no qualms about what I was doing.

I decided to do away with a sub panel and go with a simple dedicated line for this one.

Given that the AC that I put in the room only calls for a 15 amp circuit and draws 5 amps, I've got tons of spare capacity on the circuit that I ran, enough that I may tie into the circuit to put a ceiling light in.

That would fail in my jurisdiction on at least two grounds: arc fault service interrupters are required in bedrooms; a conventional receptacle would not be allowed in the floor--debris falling into the receptacle can result in a short circuit.

Otherwise, ok.

When I used to do renos, I'd take a shortcut--run the wires outside and down the wall in a conduit and then back into the panel. But these were tightly packed together three-storey semis.

Thank you for posting your adventures. I know every time I mention I want a light run or worse set up A/C in a bedroom, DH groans, LOL. Thankfully, our house had a new breaker box, but nothing was labeled. So, DH eventually got fed up and we labeled everything by walking around the house seeing what is turned on/off when we switch a breaker. Much fun!

"That would fail in my jurisdiction on at least two grounds: arc fault service interrupters are required in bedrooms; a conventional receptacle would not be allowed in the floor--debris falling into the receptacle can result in a short circuit."

Read my post again.

It's not a bedroom, it's my Mother's office.

It's not a floor mounted receptacle, the box is surface mounted on the wall and the wire comes up through the floor, protected by a piece of heavy-duty Carlon conduit.

Got it.

But here the building inspector decides what the room is. And if I dared tell him/her the room I'm in right now was an "office" I'd be violating zoning. Indeed, the electrician labelled it a "bedroom" on the panel when I built the house.

This is just to illustrate that electrical safety is not the only thing you have to contend with.

I sure hope your Mom appreciated all your hard work! I once offered to change all the switches and receptacles on my mother's then 50-year old home. She said, "no way, you're not a licenced electrician, only a licenced builder."

Adding insulation would help with the heat problem. Nowadays there is insulation made from either recycled newspapers or blue jeans that is much better for the environment (and people) than the old pink stuff.

We finally had the whole 1910 house rewired last year. When we moved in 20 years ago we simply added new wiring but kept the old knob and tube. As the electricians were working they kept saying that they couldn't believe what they were seeing and we were lucky the house didn't burn down years ago. I sleep better now knowing how much safer it is.

"Adding insulation would help with the heat problem."

There's no way to add insulation.

The house is structural 3-layer brick.

On the interior of the brick shell there's 3/4" furring strips, to which is nailed lathing, to which the plaster is applied. That's the interior walls.

That construction is exactly why I couldn't pull the wire through the exterior walls.

My Grandfather dealt with it by using a combination of Wiremold surface mount and low-voltage wiring and switches on exterior walls where he could.

The attic is insulated, but when the summer sun pounds on the bricks, the entire shell heats up like a brick oven.

The house I grew up in was even older than Mom's current house, but it was wood construction, so we could pull wires through exterior walls.