Traveling to Marseilles and driving to Barcelona the end of Feb....will be in Barcelona for 5 days and then taking train to Madrid for flight home. I have a 5S and curious what best option is for data plans - either setting up with Verizon first or buying local SIM when landing in France (or getting prior)....what is best route? FYI - I am a heavy data user but can throttle it back a bit as needed. Still, would like a gb or 2 for the trip. Thanks.