This is a great place for quick access to the airport. It's like a 5 minute drive.
It looks like parking in the area can be a bit challenging, but we lucked out and found a nearby spot quickly. Nice Indian restaurant right next door if you'd like a change from Spanish cuisine.
A note to anyone planning on returning a rental car at the airport: The (terminal 4) rental car return road is a single lane road on the right, *before* the parking toll exit gates. It is very, very easy to miss as it looks more like an EXIT for rental cars or some sort of service road than a rental car return. It has a gate at the entrance to the road, but it will open automatically for your rental car without you having to take any action. We missed this road on our first pass and pulled over at the manned booth at the side of the toll lanes to inquire. Within 30 seconds of me pulling over, a half-dozen other cars also pulled over and people were getting out to ask the same thing. They literally have a big, blown-up picture of the rental car return exit with a red circle around it hanging in the window as almost everyone seems to have trouble with this. Perhaps allow some extra time to get this done just in case. We spent an hour doing this when it should have taken about 10 minutes.