Help! July 22- Aug 10

It can be really hot in most of Italy at that time of year. I love Sicily but would urge you to park that idea until you can travel at a different time of year. You could head to the Dolomites (actually staying up in the mountains) and be reasonably sure of pleasant weather. The area is German-speaking and not what most people think of for a first trip to Italy (nor does it fit particularly well with your interests), but it is lovely and has lots of great opportunities for walks. Bolzano (very pretty, but a valley city that can be very hot, so not recommended as a summer base) has the Iceman on display. I suspect this might be more appealing to your son than baking in Florence, though heaven knows the art and architecture would be superior there.

Of course, all reasonably accessible mountain areas are popular in the summertime, but I spent about a week in the Dolomites and the valley cities two summers ago, and I didn't find the area unpleasantly crowded. The trick would be locating lodging in the mountains.

It's hard to know what else to suggest since weather can be such a major factor in one's enjoyment of tourist activities.

Italy will be hot and Spain hotter. That does not mean you should not go. You have 18 nights so you have time to take it slowly. Do not schedule too many stops. Maybe a few nights in the Dolomites as suggested for outdoor fun and natural beauty, then perhaps 5-7 nights in an agriturismo in Tuscany or Umbria. Pick one with children's activities and a pool. It will be a great place to hang out on hot afternoons after day trips to hill towns. (Make sure it has A/C.) Rome is not impossible; you just have to pace yourselves, hit outdoor site in the morning, rest in the afternoon, schedule evening outings (there are many things you can do at night).

Pompeii will be awful with crowds and heat. Instead, try Ostia Antica outside of Rome and GO EARLY.