Jay it’s not that long, just take a break every couple of hours. I did London - Nice in one - easy, no motorways all French D roads (equivalent to UK A roads). Fantastic ride for you on the cards, keep hydrated or your concentration goes… Suggest you go via Geneva - Chamonix - Italy via the Mont Blanc tunnel (how long can you hold your breath for?) and descend into Italy via the most unbelievable twisties.
I’m not jealous, nooooooo 
Enjoy Qx
Hrm, decisions, decisions! I’d prefer my own bike of course.