Let me add my praises of both the apartment and Javier as the host. Every last amenity well thought out and the food he left us was helpful all week long. Loved the coffee!
We rented a car for the week and my advice is to not do that unless you get a small one as parking is tight, not just in Barcelona but in the other towns as well. And you should have at least a rudimentary knowledge of the language as we sometimes found ourselves at the wrong toll booth or parking in a restricted area that had signage but no road markings. The train system is probably a better choice for getting out of the city.
The Ramblas out front was fun to walk and be able to find any food or drink you could want, well into the night. We were vigilant but always felt safe in the neighborhood. Definitely needed a second week to see more of Barcelona. Hopefully we will be back and would certainly stay here again.