Looking at your plan - it sounds exhausting I have to admit.

When I only add your minimum stays in every area I get 13 days, and that is without counting the days to travel. E.g. getting from Northern Italy to Southern Germany will be about a day. Same for the travel to the Nether- lands or Paris.

To judge where you might/should focus, it would be great to know what you like to do there. Are you (as a family, mind the teens *g*) into hiking? Museums? Night life, concerts, theatre? Do you like castles or rather zoos? Technics or literature? Do you have any special ideas what you want to show your family as "old Europe"?

Atm it seems to me that the only area you do justice to would be Florence. For all the others - as soon as you acclimated yourself in the surrounding and culture you are on your way again.....

Waiting for more details, Baerbel near Stuttgart