Wow, nice! There is too much to say about all that you could do, see and visit during that trip. I limit myself to posting random things: I understand Ypres (no Bruges? Maybe you already saw it or there is no interest or you will visit our city another time
). I notice you cross the Belgian Ardennes and then you will drive through beautiful regions here and there. It’s not bad but a bit like what I will write down about Italy…
Koblenz looks nice (also: Moselle wine). Not much to say about the more than 800 kms route Koblenz-Gutenstein: didn’t do that yet. I visited Austria many times as a child, but this is an area that has not been rediscovered for me until now (but this summer we’ll first do Switzerland).
The Italian Lakes: mostly beautiful region but only been there twice (there are bigger experts here on that area). I found it quite busy in the towns close to it and on the way there and even some areas not nice to drive around at all. The Dolomites (aka the Southern Alps) on the other hand, really impressed me: just drive through them on the alternative roads.
Actually, I have only visited Italy a few times and have just a bit mixed feelings about this country: sometimes beautiful (just enter Italy along the Alps/ or also: The Liguria region is beautiful and whimsical) but a little further on only industry and unattractive cities. As an example: Modena: drive there and you will understand what I mean (although the Ferrari museum is not to be despised). I will definitely visit Italy again because I think it has even more beautiful things in store. I've been to Pisa, Sienna, Firenze, Lucca, Venice (whatever they say, it's definitely worth a visit because this is a must see): I enjoyed these cities very much. It's just, well, sometimes the way there and others totally unattractive towns and villages that you will cross. I understand that this is the case in all other countries, but I just want to nuance Italy a bit. So don’t misinterpret me: I do like Italy but with a twist. Too bad you don't have children with you: they love children
! To conclude Italy with a highly positive end note: South Tyrol with its Dolomites and passes is beautiful! But then again: I love driving in the mountains.
From Chamonix to Honfleur is again roughly 800 kms and I can't begin to say what you could do (but I guess that you might just cross it and that it is not the intention to discover and visit).
Honfleur is a beautiful harbor town, definitely worth a visit and if you like fish soup, fruit de mer, definitely do it! I suppose you then drive to Calais to take the Ferry back (or Chunnel) well: you can do this via major roads or -and I strongly recommend this one- the D940: you take that after crossing the Pont de Normandie. From now on you pass nice villages and of course also Boulogne-sur-Mer (you are still on the D940) and you also pass Nausicaá there. Cap Gris Nez and Cap Blanc Nez: worth a stop Anna picture.
You will cross beautiful countries, enjoy and have a great trip!