We used the Castellmar Apartments for our weeklong stay outside Barcelona, and thought they made an excellent base for day tripping around the region. Most evenings, we came back after our day of sightseeing and could easily change our clothes and walk across the road to hang out on the beach or grab drinks and a bite to eat at either one of the chiringuitas while the kids played on their beach toys or go up the road to the restaurants off Passeig Maritim.
The apartment we were in had a front room with a futon and dining table, then a galley kitchen with a small refrigerator & microwave, and a 2 burner cooktop. There were plenty of glasses, dishes, flatware and cooking pans and utensils, but if cooking at all you'd need to pick up all the basic staples from salt, pepper and oil up through whatever you wanted to cook. We bought our groceries at the Carrefours in the area - the one in Gava had the largest selection by far.
You could stay here without a car, as the train station into Barcelona is about a 15 minute walk, and there's enough restaurants off you don't want to cook, but for our trip and the places we wanted to visit we rented a car. The parking was off street, and we never had trucks trouble getting a parking space. The property is managed by Apartmentos Marfina across the street, and and we would recommend routing GPS directions there, as ours kept routing us to the wrong place unless we typed in the street address. Their desk was always open & friendly!