Thank you all for the help. Actually, Jacob, we've flown into CDG many times, but have always just taken a reserved shuttle bus to our (rented) apt. in the 5th. This time we're going to La Rochelle, and the direct train from CDG to Poitiers leaves at 8:55am, which was too tight. I'm also considering a private car from CDG, which would be waiting for us - little more than the cost of a taxi, although of course the problem of traffic would still exist. Ultimately our success will depend on whether our flight arrives just about on time, I would guess.