When having a shower, do not pull the string with the red knob on the end, it is not the extraction power switch, it is the "call the receptionist, I've fallen over" cord.

Those cities are excellent for a first Italy visit.

With train travel taking up a good part of the day, I’d add at least 1 night in Venice even if during Carnival. Add a day in Florence if you want to do a day trip to Pisa and/or Lucca. 7 nights in Rome is a long time, for me. Three nights minimum per city will be easier on all of you, not just your parents, than shorter stays. I have no idea how old they are but consider their physical ability when scheduling days and how much you want to fit in. I’m 54 and could be your parent (I have no idea how old you are either) and very rarely have to adjust anything compared to a younger person - though I likely have a very different travel style than someone younger. Do either have physical limitations? If not, don’t worry too much. If so, be sure to have ways to use public or private transportation to get back to your hotels. In Venice, maybe consider a hotel convenient to a vaporetto stop so there’s less need to walk a long distance after a long day.

If you book trains ahead, there are good discounts but no flexibility so decide well ahead what you want to do. Since it’s winter and days are short, it might be a good idea to plan to arrive in each city during daylight hours? I don’t like to arrive in a city or at my hotel after dark but that’s just a personal preference.

You’ll all love it. Enjoy your planning.

Even 7 nights in Rome yes a bit much IMO -how about adding a couple to Florence and maybe do an excursion by bus to say Siena - classic Tuscan hilltown and or Pisa or Lucca.

less time in Viareggio>

Viareggio can be relaxing but in winter mainly empty but is a good base to jump to Pisa by train or bus to Volterra. Why not go to the Cinque Terre for a few days- nice in off-season and weather may be fine - was when I was there one January.

I am also planning a trip to Italy in Feb. Not our first time to Italy but we are planning Florence(4-nights) and Rome(2-nights). Taking one day trip from Florence. The sites are beautiful in Rome but I wouldn't miss spending at least a couple days in Florence. Its one of our favorite Italian cities (Assisi and Orvieto are also on the list of favorites!)
Enjoy!

Yes Florence is so easy to stop in even if just for a day stop when going between Venice and Rome or v.v. Shame to just pass thru it.