I recently went Roscoff down to Montpellier, Marseille, St Tropez, Cannes, Nice, *Monaco (did a lap of the f1 track 2 days before the race when it was open to traffic. :-). Then Pisa, Lucca, *Florence, Verona, (I thought about Venice, but changed my mind), *Lake Como, *Stelvio pass, to Switzerland - *Furka, *Gotthard, *Grimsel and *Susten passes, them up into Germany *Autobahn and Black Forest home.
Anything with a * I'd definitely recommend.
I did 2973miles in 9 days. Travelled on my own and hotel hopped, booking as I went.
I chose not to camp, as everytime you want to get off the bike and explore somewhere, unless your camping gear is secured/locked to the bike I would have had to lug it around.
I had an awesome time. Originally I intended to ferry down to Santander/balboa for the first leg, but my ferry was cancelled last minute so I rode down west/central France, which was very wet, a bit cold and a bit boring.