RThanks everyone! I checked out the three links. VBery helpful! I'm glad to know that the Yellow and Blue Zones are also differentiated with numbers / letters for the tracks. Really helps. I know my SNCF voyage number so will use that as the source instead of the city (it makes sense of course that the destination is what is shown as opposed to the city I'm going, but I didn't consider that!). And I just googled the number and saw it's Paris>Marseille, which makes me think that the train will already be parked on the platform as opposed to arriving on the platform, so that should make life a bit easier as well. Or so I hope

Thanks also for the tip about the school vacations - had no idea

I expect to arrive at the station an hour or so before the train departs so I'm feeling very comfy, esp with all this extra info. Thank you all again.

Michael