De Gaulle Airport to Strasbourg

There are several direct trains that take about 2-1/2 hours.

This is something you can find out by looking at sncf ( French rails) , It appears you can easily get a train from CDG, but a lot depends on timing, when does your flight arrive? Allow at least 3-4 hours before you book a train.

There are a small number of trains per day directly from CDG to Strasbourg: you can check when they leave and book tickets at www.tgv-europe.com. You can significantly reduce the fare by booking around 3 months in advance, but the cheap advanced tickets are strictly limited to a single train, which may not be safe if you are flying in from the USA. If there are no direct trains, the trip into Paris won't be too bad, as the trains from CDG arrive at Gare du Nord, and Gare de l'Est, the station for Strasbourg, is within easy walking distance.

Since you are at the airport, why not fly? We did last year. The Strasbourg is connected via rail to downtown.

If you're flying on Air France, some of the "flights" from Paris to Strasbourg use the train from CDG. If you book it this way, all on one ticket, you don't have to worry if you miss your train, as they will put you on the next one free of charge. And, whether you go to Strasbourg airport (SXB) or Strasbourg train station (XWG), this may not cost any more than flying into Paris. Therefore, it can be cheaper than booking a separate ticket from Paris to Strasbourg - particularly if you opt for a fully exchangeable ticket, which will be more expensive than a non-refundable one). For yet another option, Lufthansa operates a bus from Frankfurt airport to Strasbourg (code is XER, and it stops next to the train station). The bus is available to anyone (I booked it as part of my flight, and again, by including it in my flight it didn't add much to the cost). Details here: http://tinyurl.com/bola9lf So, when searching, put in Strasbourg as your destination, and choose "include nearby airports" to pull up all your options.