I like old stuff. I like old books, old buildings, old paintings. I even took a Roman Medieval History class in college because it sounded interesting, and it wasn't even a requirement or elective. So I know that going into Italy, I'm going to want to stay and see everything. Which, of course, isn't going to be possible on this trip, but I don't want to minimize my time, either.
I was originally going to only visit Rome, but then everyone said I had to visit Venice. And Florence & Tuscany. And Naples & the Amalfi Coast. And Milan. And Sicily. And Pompeii. And Cinque Terre. Until I got to the point where I could have made my entire trip just in Italy. So I have to draw the line somewhere, which at the moment appears to be Amalfi and not going further south.
My tentative stopping order is Milan (day 46), Venice (days 47-?), then maybe down the west coast on the Adriatic to places like Ravenna and Ancona before crossing over to Rome on the east coast. Maybe a day or two south to Naples, Pompeii, and Amalfi. Back north to Florence, Pisa, and Genoa along the Italian Riviera coast through the five small towns that make up Cinque Terre, over the border to the French Riviera and Monte Carlo, Monaco. Definitely going to need the guidebooks to help me here.
At this point, I'm guesstimating a good 12-14 days to do all that. And after Monte Carlo and whatever else there is on the French Riviera comes Barcelona, Madrid (plus all the side trips from those two places), Gibraltar/Tangiers, and Lisbon, and you can see why I'm looking at 70 days in Europe.
But then I'm going to have to go back and look at my itinerary again to see what I can cut out so I have time to add stuff (side trips and days off) on the way.