My flat is just in front of San Marcos's Castle. It's a castle from X century and it is also next to the maritime station, so you can go to Cádiz by ship (It's a beautiful journey that won't be longer than 15 min. Highly recommended). In the case you need it, I could lend you a bike to go for a ride if you want to. The house is 15 min away walking from the beach.
The location is fantastic to enjoy your visit to El Puerto.