Another option is South then South-West rather than West then South-West: Lodz - Vienna - Graz - Venice - Marseille - Barcelona - LECU. This avoids the Pyrenees and most of the Alps.
If you opt for this, consider going a bit out of your way to include LJPZ Portoroz - recommended by many as the finest G/A field in Europe - and certainly include Venice's G/A field LIPV San Nicolo (sp?). But speaking against this route is the complicated, almost forbidding airspace around Nice.