I just completed my first trip on the French TGV rail line, and thought I would post some "I wish I had known" info regarding that experience which might be helpful for others in the future.
I ordered my tickets on-line a little less than a month in advance. I followed the advice of other posts and clicked "England" rather than the US as my location, and for the most part did not have too many hitches with the site. UNTIL I went to print out the actual tickets. I had ordered tickets for two separate trips and was able to print the first one without a problem. However, when I went to print the second one just a minute later the site did not offer me ANY option for printing--only pick-up at a train office or station kiosk. Well, okay, it was frustrating, but I figured since I would already be there I could do that.
Trip #1 went smoothly. I traveled 2nd class, and it was very comfortable--way nicer than most economy class airline flights. The one flaw is that there isn't much room for luggage. The overhead racks only had room for backpack sized bags (not even carry-on sized bags would fit), and the front and rear compartment luggage areas weren't really big enough for all the bags people brought on--it was a hassle. Also, the "cafe" car is crowded and rather expensive, so I'd suggest picking up a sandwich, drinks, etc. and bringing them on board instead. Just about everyone in my car did that.
Trip #2 was a real mess because of the ticket problem. When I arrived with a French friend at the smallish station, there was only one person at the ticket office counter and about twelve people ahead of me--all of them seeming to be little old ladies with many looooong questions. With less than 25 minutes remaining before departure my friend advised me to try the kiosk dispenser instead.
The touch screen menus were pretty clear and worked well until it was time to "insert original credit card used to order ticket." While I had had absolutely no problem with this card for the original order or any other purchases I had made during my whole stay in France, the machine simply would NOT accept it.
With visions of missing the train and thus my flight home, it was time for desperate measures--I started over and bought a new ticket. Still, none of my three credit cards were acceptable to the machine, and with just a few minutes left before departure I was very lucky that my French friend volunteered her card and it worked.
Because it was last minute there were no 2nd class seats available, so I had no choice but to buy a more expensive 1st class. Well, at least I got to experience that, too :-) The seats were very nice, although not hugely better than 2nd class. The luggage space, however, was much better. And most everybody was still eating those take-out sandwiches!
I will be the first to admit that if I had left more time for ticket retrieval I might have been able to resolve the problem with the clerk at the counter and have saved a lot of stress and money. Although a bureaucrat is a bureaucrat, and there's no guarantee the clerk would have been any happier with my credit card than the kiosk was... But I made it home, and now for entertainment's sake am going to attempt to get a refund for my unretrievable ticket. Bonne chance!