Mary is a very pleasant host, and her place is a wonderful find. You'll receive key access so you can come and go as you please. She reserves a place in her refrigerator just for guests to store food and filtered water is available to fill bottles. She has a small, well-behaved dog that is not allowed upstairs (where the AirBNB room is), and he never woke me up at night. There are several fantastic cafes/restaurants within a few blocks of Mary's place (try Beet Box and Watercourse!), and is just a mile from downtown Denver. There is a hospital nearby, so you can occasionally hear sirens in the distance, but they didn't really bother me much at all. The neighborhood she lives in is very nice and I never felt at all concerned about walking around (which is not something I can say about other parts of Denver).
Overall, I'd recommend Mary's place to anyone without hesitation!