CDG (Paris Airport) to Gar de l'est QUICKLY

I don't think you have a prayer. You need to figure on close to an hour from landing until you get out of the arrivals hall with all the flights coming in that time of day. Morning surface traffic could well make the drive as much as another hour. If you used the RER to Paris Nord, and then sprinted like hell to Paris Est, you might make it, but I doubt it. Why not just catch a tgv from the airport station to Strasbourg. They run frequently during the day. There's one at 7:48 (tough), 9:27, and 11:00 that will get you there in from two and a half to three and a half hours without having to go into Paris.

I assume this is on a Sunday, because the German Rail site only shows the 8:40 for Sunday. I think Al overstates the case just a little, but there is still a nontrivial chance you could miss this train. Traffic should be light on Sunday, which is a plus for you. But you still should hedge your bets. Your options are not too bad. You can either (1) buy refundable tickets online, and be prepared to eat the cost of your reservation if you can't make the train, or (2) buy your tickets at the counter before whichever train you can make. In either case, have a backup plan for walking around Paris, even staying for lunch, if you can't make the 8:40. There are trains every hour starting at 10:24. I had a flexible plan like this with very similar hours, trying to get to Burgundy, and got lucky, even with the delay of a checked bag. I was in Beaune well before lunchtime. Maximize your chances by packing light and carrying your bags onto the plan.

I was afraid of this. What a snafu on my part! Holding my tickets right now but can change them departing directly from CDG at 7:46. Would this be doable or should we just wait until the 10am trains? Any thoughts? Thanks for the advice.

I missed the Sunday business completely, thus: As Adam said, the taxi will make it. I can pass the airport exit inbound to Paris on Sunday and be at Nord/Est in less than fourty-five minutes and the taxi guy probably knows a few tricks I don't. The 8:40 departure from Est takes a change from Nord to Est and another one at Metz. The duration if four hours. The 9:27 departure from CDG has a change at Marne and takes 3:40, arriving twenty-five minutes later than the departure from Est. I'd save the heartburn by changing the tickets and poking around the airport. Who knows if the plane will be on time and exactly how long it will take to get out the door of the arrival hall - - I've seen thirty minutes to well over an hour from stepping off the plane. Plus, sometimes flights don't pull up to a jetway and you have to be bussed to the terminal from the middle of the tarmac.

Thanks for the advice! We've decided to stay at he airport, taking the later TGV directly from there to Strasbourg. Someone even suggested a restuarant at the airport that's supposed to be quite good and will give us something to do while we wait.