First time travelers to Italy and I've had a few people recommend reserving early morning access (before opening) to the Vatican museums and Sistine Chapel while in Roe as well as the early morning access to see the David and to climb the Duomo in Florence. These are both a bit pricey for our family of four (2 adults and 2 teens) and we will likely only pay for one of those experiences. I am wondering if anyone has experience with either or both and could share thoughts on what might be most worth the expense.
We will visit the Vatican and Accademia either way but will only do an early entry on one. Also, is there an affordable option to climb the Duomo?
Additionally- Any other great tours you would recommend in Rome, Florence, or Venice?