Here's my suggestion. It primarily combines the trips to Italy/Austria into a single loop while giving time in Florence rather than Milan and also gets you to Venice.
Day 1-3 - as described
Day 4 - delivery then overnight in or just south of Munich (driving after your day at the Welt either means you'll be really tired or you'll need to skip part of the experience, which would be a shame)
Day 5 - drive to Florence - we made an early start and got there by late afternoon
day 6 - in Florence
Day 7 - drive to Venice
Day 8 - in Venice
Day 9 - drive to Salzburg (you'll have to to poke around in the afternoon)
Day 10 - morning in Salzburg, then drive to Vienna
Day 11 - in Vienna
Day 12 - drive to Krakow
Day 13 - in Krakow
Day 14 - drive to Prague
Day 15 - in Prague
Day 16 - Drive to Nurmburg
Day 17 - Nurmburg, then drive to Munich
Day 18 - Drop can and fly home.
Last edited by milepig; 01-11-2013 at 11:22 AM.