car rental one way--common? possible?

Sure. Last winter we picked up in Frankfurt and dropped in Munich for no charge. Just check with the rental company. It is fairly common. However,dropping in another country can get expensive.

Contact Andy Bestor at Gemut.com about this. If there is a way to drop the car just over the border in Germany, he will be able to find it for you. He will also find you the best rates. In 2011, we rented a car in Stuttgart, drove it for 2 weeks in the Alps (Germany, Austria, Italy, Switzerland, France) and returned it in Lorrach, just over the border from Basel to avoid the extra charges for dropping it in a different country.

Where they'll really get you in the pocketbook is when you drop a car outside it's home country. Many travelers will drop the car off in a location along the train lines and take the train to their next destination.

What David said. You can always drop-off in a different place but it can be expensive to cross a border and drop a car. Sometimes you need to, but make sure to consider the cost. If you're planning multiple countries, it may be better to rent in one country, drop the car, cross the border, then pick up another car.

Want to try pricing your options? Go to the AutoEurope web site and play with pick-up and drop-of locations. Best to pick up and dop off in the same country.

Since Strasbourg is just over the German border, it shouldn't be difficult to return to Germany to return the car after your Alsace driving, then take a train back to Strasbourg to continue your France sightseeing.

Or you could even drop your bags at your hotel in Strasbourg and then drive the car back over the border and drop it at the agency in Germany.