I'm going to assume you're going to do this VFR. In that case, I would suggest you avoid high terrain such as the Alps and the Massif Central in France. So route north of Switzerland, and in France get into the Rhone valley ASAP and follow that down to Marseille. Then follow the coast, turning inland into Spain after the Pyrenees, or maybe a bit north of Valencia. Or something like that. But high terrain leads to more challenging weather and to a lesser extent more challenging airspace, and you don't want those on a ferry flight.
Once you've got that route sorted, then look for airfields. But "interesting" would be low priority for me. I would first look for fields that are full fuel/empty bladder distance away from each other (300-400 nm), and where a relatively quick, painless and cheap turnaround would be possible. And after a 600-800nm day, I don't think I would be up to exploring an "interesting" feature nearby. A decent hotel would be my number 1 priority.