best location to airport and train station?
 

Someone suggested this area of Barcelona to stay: (Barrio Gotico, Born and La Barceloneta, Eixample).
But wondering if one area is better for getting from the airport and staying a few days, then getting to the train station. I head to Sitges after Barcelona.
After Sitges, I will train back to Barcelona for a few more days, then fly to London. Is one area better to locate myself then another? Or does it not matter? Thanks

Don't matter as the metro/commuter trains go everywhere from airport and to train stations. Both airport and main train station are rather removed from the historic center where I would stay - again easy to go by metro/commuter trains anywhere.

While Gothic quarter, el Born and Barceloneta are quite small in size, Eixample is a huge chunk of the city.
For the latter, I would check the maps where exactly any hotel etc was - and preferably near a metro station.
Going to Sitges is no big deal - you can catch the regional trains going there at several stations in Barcelona - not only at Sants.

We stayed in El Born and highly recommend the location. We took taxis to and from the train station, very cheap and easy.

The suburban trains (Rodalies) from Barcelona to Sitges start at Estacio de Francia and call at Passeig de Gracia and Sants.

For many locations in Born or Barceloneta, it's just a 5-10 walk to Estacio de Francia.
For locations in "central Eixample" or around Pl Catalunya, Passeig de Gracia station is a short walk away.

You don't even have to plan the "travel" from Barcelona to Sitges as there are several trains per hour.
Just take any train with destinations "Sant Vincenc de Calders" or "Vilanova i la Geltru". All of them call at Sitges.

Last trip I stayed in the Eixample which I much preferred to the area near the Ramblas and the old city. I was walking distance from the airport bus which leaves from Plaça de Catalunya, although I had to use the metro from the train station.

yeah, I did that also and think the Eixample is better suited for the airport in a couple ways. First, depending where you are, you could be near the airport bus stop (the incoming one is at Universitat, I have stayed near there). But if you take a taxi, I believe the suspect the streets are easier/quicker to get there than places like Born which is an old area with small streets. I could be wrong, not sure. But Eixample area is closer to the main train station, also. At least the part where I stayed, which was in-between Psg de Gracia and Carrer Granados, not the side where Sagrada Familia is.

Thanks everyone for this info. Have another urgent question: I may have a very early flight out of Barcelona on Sunday, September 16th. 7:40am to be exact. Which means being there 2 hours in advance I believe. 5:40am. So will I have trouble getting a Uber or Taxi to the airport at that hour? And how much time should I plan for this? Once again thanks so much for your info and support, greatly appreciated!

Probably not, but I don' t know for sure as I took the airport bus. First one should get you there at 5:35.

Direct bus Barcelona city center - Airport El Prat | AEROBÚS