We did the Med. cruise over a year ago out of Barcelona...no kids or grandkids. A couple of things to consider:
1. I got pickpocketed in a gift shop across from the entrance to Park Gruell. Didn't lose much $$ in my pocket, the serious stuff was on a belt inside my shirt. However, beware of scams and kids (small hands) that make Barcelona the pickpocket capital of Europe. There are YouTube videos on this business.
2. Monte Carlo is a tendering port. The day we were to stop the water was too rough and we had an "at sea" day instead. The next day, formerly "at sea", became a port stop at Marseilles, France.
DCL whipped up about a dozen excursions there. We went to Avignon and to a winery...bit of rain, but awesome.
3. Pisa is a long bus ride from port and be prepared for loads of venders near the entrance. People were everywhere doing the obligatory hand pushing the tower upright photo. We did not have time to climb inside, although we had a pass for the church next door and the tower. It is what it is, however. If that is a high priority for one your kids you gotta do it.
4. The DCL excursions to the Coliseum and the Vatican worked like fast passes to get us in ahead of long, long lines. Perhaps the on shore companies also offer this advantage. A lot of these Med. sites are loaded with visitors, and security is tight at some. While they can be a hassle to get through, they are the only real deals. Las Vegas copies are just not the same. Try to take your time because a lot of history was made at each venue. With the increasing tourists, it won't be long before these sites will be timed and or restricted to drive-bys.
We loved this cruise, even though the port days were nearly 8am-5:30pm. DCL allows for that with your dining. You might tell your wait staff what time you are coming back from your excursions (for early seating only), so they can plan accordingly. Have a great trip and be sure to check out the characters' outfits.
This cruise was the last of the season for the Magic in the Med., so we made it a B2B with a WBTA...a vacation from our Med. vacation.