Elsy's apartment is very much as described, and she's an excellent host. She offered (and given our evening flight) to arrange a transfer from the airport for a very reasonable price, and this made arriving much simpler.
The apartment is as described and in an excellent location for the more historic neighborhoods of Santiago.
Also others have noted the apartment faces a large street and therefore traffic noise is high, and the windows don't block a whole of it even if closed. If you're sensitive to noise, this will likely be an issue.
The apartment also does not have AC and faces the sun, so if you're used to keeping things cool make sure you know what the weather is going to be like while you're in Santiago.
One issue for those who want to cook their own meals: the range knobs aren't labeled, so some experimentation is required to find out what is high and low heat; the best I could tell was that up to about 11:00 in clock directions would be high heat.
All in all Elsy's apartment is an excellent value for the location and price as well as the (hard to find) king bed.