TRAVEL EUROPE WITH KIDS

In the late 80's I was drafted to drive my parents around England, Scotland and Wales for 3 weeks. They were both over 70 and couldn't rent a car at that age. In retrospect, we all agreed that more time and fewer places would have been better. We drove on a few 4 lane highways, but mostly on narrow two lane roads that were built wide enough for 2 single horse carts to pass each other. When you add driving on the wrong side of the road from the wrong side of the car, it required extra concentration. Mostly, I was nervous all the time.
In your case, add "are we there yet?" children to the mix. I suggest reducing the number of countries and/or increasing the length of the trip. If nothing else, you won't feel like you need a vacation from your vacation.