6-7 days in Italy in June

...alternate options.

Consider flying into Florence and out of Rome. Or the other way around. That will save time backtracking to the airport for your return home, and might save some money. Do your seven days include arrival and departure days? If so, you will only have five full days. In that case you might want to consider spending the entire time in Florence. Just food for thought.

I would agree with TCs suggestion and fly in and out of Florence and spend your entire time there. Two nights in Rome only gives you one full day, and that is not even enough time to get your bearings, then you will lose another half day getting from Rome to Florence. The sights in Rome are all so busy that you will spend a lot of time in line-ups if you don’t book tickets well in advance that allow you to skip the line. Florence has some great sights in the city, and is a much smaller and easier place to recover from jet lag.

Rome + Florence + Bologna + Cinque Terre + Siena = 5 days, mostly spent on trains or highways. With just a week, stick to one or two places. Either Rome or Florence could fully occupy you that whole time. If you split between them, it would be a good idea to fly "open jaw," into one and out of the other, to save backtracking.

If you are not interested in history or museums, what are your interests? Most of what tourists go to Florence, Rome and Sienna for are related to the rich history of these places, including many wonderful museums. I'm not trying to be a smart-a**, I'm really curious what drew you to want to visit these particular cities. Once we understand that, we can give you opinions on your timing and what you might want to drop so you're not spending your whole week on trains.

We(mainly kids) are interested in Italian cuisine and seeing the local culture and scenic beauty. If we have two do only two cities please suggest which could give us the best memories. We would have 6 days excluding travel.
Thanks

6 day, that is almost enough to see Rome well.

If you still want to see 2 cities, then I might suggest flying into Venice for a couple nights. It is much closer to Florence by train, and is one of the most unique cities in the world, and is easily walkable. There are some experiences to be had there you won’t find anywhere else such as learning to maneuver a gondola, mask making, or glass blowing.

I agree with only six days on the ground, you have time for two cities max. I'd pick Rome + either Venice or Naples. I love Florence but if you really aren't interested in the history and museums, it kind of seems a waste. Venice definitely is a one of a kind place so I'd probably lean towards there, but I'm throwing Naples in as a wild card because it's also a vibe all its own and the food is amazing.