Things to do around the Vatican

Why not go ahead into St. Peters? The security line could easily take half an hour, sometimes more, and then you could be looking around the Basilica while he tours. You could walk down to the Tiber and up to Castel Sant Angelo and then back to the Piazza for security. Your husband will come directly into the Basilica from the tour so you will want to meet him inside the church. You could also visit the tomb area where the popes are buried underneath the basilica; the entrance is inside the church. Climbing the dome while interesting is probably not something to do with such a big baby as she would have to be carried.

My best advice - give your daughter tons of time to rest and play. Maybe stay in the hotel while your husband does his tour. I took my son to NYC and a Canadian cruise when he was 21 months old and he was so exhausted the whole time, being out of his routine, that he cried at every meal. We traveled with two dear friends and they said we did not eat a single meal without tears - his and ours!

Seriously, I hope you guys have a fantastic time, but please allot for tons of rest time for your baby girl. She will need it more than you realize.

I haven't been to the St Peters without doing the Vatican tour. I was unaware that there would be space for us to run around in a courtyard without bothering anyone! Do you know if I would be able to take a small backpack in? diaper bag?

Perhaps the best gelato in Rome can be found at Old Bridge. This is across the street from where people line up to get into the Vatican museum.

The only "courtyards" I know of at the Vatican are inside the museum confines and I don't think they would be accessible to you. There is the huge piazza in front of the church but it'll be busy and that vast expanse of pavement might be uncomfortably warm.

There is a park (Parco Adiano) with a playground right behind Castel Sant'Angelo, down the street from St. Peter's. Google up an earth view of the castel and you can see it on the northwest side: look for two dark squares and zoom in. This might be a more kid-friendly place to spend an hour than the piazza. A little about the park:

http://www.imlearninghowtocook.com/?p=261

Otherwise, you could just go inside the basilica and wait for him there.

I second the recommendation to get gelato at Old Bridge...seriously the best gelato place in all of Italy! Tiny little hole-in-the-wall place that serves generous portions. There's always a line but for good reason!

I second the idea of the park at Castel Sant'Angelo. There is lots of green space and not many people.

I'm definitely agreeing with the Castel Sant' Angelo park suggestion; it's what 18 month old me would want to do! She's not too young to appreciate pigeon chasing in the square just outside the Basilica either :)

The Old Bridge was very close by and had excellent gelato. There’s also a chain of pizza by the slice shops called Alice I’ve seen throughout the city and one of them is very close to Saint Peter’s. Perhaps let her enjoy Saint Peter’s Square a bit and then take her for a nice gelato? Neither of these food options are overpriced either and many things just near the Basilica can be.

One hour goes quickly, so be sure that you pass through security in time to meet your husband. Anywhere in the shade is a good place to be...your daughter may be off schedule and that could be a good nap time, in a pew or in the shade of the park.