I spent 5 nights at Marisa's place, and recommend it for a simple, convenient stay.

Location: The minipiso is on a side street in a quiet residential area. It's on the ground floor, and shares a street doorway with the host's home upstairs. Walking to the historic old centre is ~30 mins. However there are lots of good restaurants and bars nearby in the Russafa neighbourhood. It's ~10 mins walk to the Jardines del Turia, Parc Gulliver and Ciutat de les Arts i Sciences. The nearest metro station is probably Xàtiva, ~20 mins walk.
Inside: The space is neat and self contained, with a living/sleeping area, and a partitioned bathroom/shower. There's a fridge, microwave, coffee machine, plates, cutlery, kitchen table & 2 chairs, wardrobe, strong wifi, loads of sockets, etc. Some nice touches were the bowl of local oranges, and other snacks provided. The bathroom was stocked with toilet paper, hand/large towels, soap, shower gel and conditioner. Everything was sparkling clean. A few more hangers in the wardrobe would be handy.
Communication: Excellent - Marisa contacted me several days in advance to confirm arrival times and give me directions. On the day of, she whatsapped instructions to get inside. Her son met us at the entrance to the minipiso and provided keys and contact info should we need it during our stay. Checkout was nice and flexible - you can leave whenever you need to and just leave the keys inside as the door locks itself on the way out.
Overall: Clean, flexible, easy. Perfect for a short stay for 1-2 people with decent walking capabilities!