When we were in France and heading for Paris, we dropped our rental at Chartres and caught the train into Paris..... so much easier than facing a big city!
I would appreciate if TA's could advise suitable place to drop off vehicle. Our last area visiting Germany will be in the Mosel area, around Bernkastel (or those are the plans at present!)
We would want to go straight to Frankfurt airport (be at airport by 7 p.m.) by train.
Thanking you, Chris