Myself, wife and 2 kids ages 7 and 17 are going to Europe for 5 weeks. We are thinking 4 days for sights in London, 2 days in Paris, then on to Italy for a month. Any advice on traveling with children would be most helpful.
I'd take them to Disneyland. (Donning tin hat) (seriously)
Since you've got such a long stretch in Italy, I'd recommend spending at least a week of it in one place. Find a home base and rent an apartment. It'll give you a chance to sit back for a bit, plus give you all a little bit more room to get a break from each other (that's a long time for the family to be together). We've done family travel in Europe, but not in Italy (yet!), so others on here may have more suggestions on where exactly to stay. You can do a google search for "agriturismo" to find farmhouse apartments in Italy. I would suggest stretching your time in Paris a bit. 2 days just isn't enough. If you can add 2 more days, that should do it.