Maria's apartment was wonderful for our family with 4 adults... my husband and me, and our adult daughter and her partner. It is smack in the middle of the Old Town of Seville, yet surprisingly quiet. The two bedrooms are on separate floors, so there is quite a bit of privacy for two couples. Maria was attentive and flexible with our check-in and arranged the cab for us to get to and from the airport, which was a real plus.
Seville is a great walking town, and this location is very central. In our six days we walked easily to the Cathedral, Alcazar, Plaza d'espana , hundreds of restaurants, even to Triana, on the other side of the river.
There are quite a few stairs in the apartment... it is on the 2nd floor, and the other bedroom and balcony are higher and might be challenging to those with any mobility issues.
The neighborhood is charming but a bit labyrinthian... so I recommend a good map!