>In Europe taking long family road trips by car as we do in the US would be prohibited and even stupid in the eyes of many Europeans.

What?? Caravan or road trip with regular car is a very common vacation in Europe. In France there are tons of free places to stop over the night. In the nordics you can camp anywhere that isn't close to someones house, even on private land. But no I wouldn't take the car instead of a 2-3 hour flight, especially as our cities have excellent public transportation.