Did anyone mention weather and traffic conditions?

We are about to start from Bavaria to Graz. I go a clear no from my son - so we will leave the Mog in the shed. And a bit I agree. Traffic jam in the full heat combined with a 300 mile ride is probably not full pleasure - it is more a proof of ...

1973 2CV AK400 Ralley
1985 plus 4 four seater
1992 Peraves ecomobil
bicycles (pedersen to recumbent)