Probably easier than the US, and with 3 people it's cheaper. Also, you can go to more off the beaten path cities like Lubeck on your way down from Denmark to Berlin. You can take a train from Copenhagen to Germany then drive most of the rest. You can drop the car off in your last German city without much more additional cost, then, train to Amsterdam. I did something similar and liked it a lot better than trips where we took trains around.

Also, definitely Dresden over Leipzig. Dresden is amazing Leipzig can be done in a few hours.