I thought I could only book 3 months in advance, but I was able to book my train tickets going: CDG 2 to Avignon. They were more expensive than I thought they were going to be. Anyways, a few days later, I tried to book my train coming back & all I see are 2 choices that are really high price. My confusion is, it says idTGV instead of TGV. What's the difference? Also, when I put in Gare de Lyon, it asked me for more info, Then I had to choose from 3 different Gare de Lyons. One has an A behind it, one had rer behind it. I did an experiment & put in march in instead of April, but same dy of the week: Wed & I had many more choices of trains at a cheaper price. So do they schedule more trains or show more when it is 3 months in advance or closer to the date? I didn't book this ticket yet. I am waiting until next week, as it'll show more trains I think. Can anyone clarify this for me?