Lexma90

If your primary interest is art and museums, keep that in mind when planning, or to avoid being too overly-scripted, when coming up with possibilities. I am a huge fine art geek, to the point of having lists of the museums of where some of my favorite artists' art is located. If you really want art, you might not want to give 1/2 a day or more to visit Burano / Murano, for example.

You have, of course, the major museums on your list. Also flag the Pitti Palace in Florence (kind of disorganized, but has Caravaggio, Raphaes and a piece by Artemisia Gentileschi); Raphael's "La Fornarina" at Palazzo Barbarini in Rome, and Caravaggio's paintings in situ at the Basilica of Santa Maria del Popolo in Rome; and if you like Bosch, a number of his pieces are at the Palazzo Ducale in Venice; Veronese's awesome "Feast at the House of Levi" is at the Accademia in Venice (it's been off view for years, but per the website it's now on display, I think). To name just a few! You won't have time for everything, but decide where you want to visit based on your specific interest. As mentioned before, book ahead for the major museums; the Borghese in particular.

Re airfares, I'm not sure if it's already been mentioned, but make sure that when you check flights to use the "multi-city" or "open jaws" option, where you fly into one city and out of another.

Re hotels, generally speaking stay as central as you can to the sites you want to see that are within your budget. In Rome, we've stayed at several hotels on the pedestrian via Coronari, which is very close to Piazza Navona, I think they would be in your price range. You don't need to book hotels now, I would probably wait a couple of months.

Re trains, the schedules and tickets won't be released until 3-4 months before the dates you will need them. I like to reserve tickets in advance, it makes me less stressed. Refer to the excellent website run by: ManinSeat61 for more details than you could imagine, including pictures of the trains, outside and inside. Fares (I'm looking at them now for our trip to Italy next months) can allow you to change to a different train on the same day, should you decide to travel a little earlier or later than originally planned.

Re adapters / transformers, I can never keep straight which I need. I have a somewhat-heavy multi-outlet device that I've had for a while that does both. I can plug in regular U.S. plugs and my phone charger (USB cord). You might want to make sure you have at least one longer cord, in case the outlet is in an inconvenient location in your hotel room. On our last trip I also took a portable charger, partly because it was a working vacation, and my phone was on its last legs. I liked having the reassurance of being able to recharge during the day if needed.

Re flight delays and cancellations (partial disclosure - I work for an airline), I would guess that disruptions will be lessened by next year, but really who knows. I buy trip insurance, but really only for medical evac just in case. If you arrive a day late, your hotel may or may not be understanding. Remember that those people need to make a living too. Try to be flexible on the possibility that you might have delays. Try to carry on your luggage if you can (honestly, all of the airline people I know do this as much as possible); if you can't, then split your luggage and one of you check a piece of luggage, and the other carry on. That way, if a checked bag gets misplaced you won't have to spend valuable vacation time looking for extra clothing, etc. to wear. We had our luggage misplaced once, on a trip to Venice. I had enough toiletries and a change of clothes, but didn't have a hairbrush. Not surprisingly, it was difficult to find one in Venice.

One, last, scandalous suggestion. You have a 10-day trip, which is not a huge amount of time. You could decide to skip one city, if you want to able to be a little more leisurely in two cities. If you're thinking about that, only you can decide which two. On my first trip to Italy, we visited Florence and Venice but not Rome, but have visited each of the three a number of times since then. IMHO, Venice is a city like no other, Rome has just so much art and history, and Florence has awesome art and sculpture, but to me is a less interesting city than the other two (other than for the art).

Enjoy your planning!