My husband and I recently spent 20 nights at Alison's apartment, located I the heart of old Sevilla. Having never been to Sevilla before, we were so lucky to have found the apartment, which is 100 metres from great restaurants and bars. Although it can be slightly noisy on Friday/Sat nights, you are right in the heart of all the action. The area of Alfalfa is very safe, with many families making this their permanent home.
The apartment is great for two people with great wifi, comfortable lounge and effective air conditioning - a must for this time of the year.
Santa Justa train station is a 15-20 minute walk or 6€ cab ride.
Once you navigate the back streets, you can be at the cathedral and all other major sites around the centre of town in 7 minutes (walking). The bull ring is a 15 minute walk, Triana market not much further and all other sights easy to walk to.
A bonus is the fresh market at The square, great for when you want to cook.
Alison was incredibly responsive to any requests, and being upstairs, able to help with anything we didn't understand.
I cannot recommend this apartment enough - we hope to come back again one day and renew our friendships and love of Sevilla.