travelling by train from athens to london in 5/6 days what is the most enjoyable route(partic athens 2 budaps)

Travelling in the summer through ital across to greece and then to the islands/athens. Any ideas for best train route/places to visit from Athens to London. Will prob go for the Budapest/Vienna/Paris route home but am particularly unsure of the route from Thens to Budapest

You will cross the old Yugoslavia south to north before entering Austria. I have not taken the train through, but I have driven the distance north to south coming from Germany-Austria-Yugoslavia. It was an interesting drive but not as interesting as driving the Dalmatian coast in the same direction. At any rate, it will be fascinating to see the changes that have taken place.