Venice, Florence and Rome in 5 nights

You're joking - right?

5 nights in 3 cities - each of which require at least 3 whole days just to get acquainted with.

With only 5 nights you don’t have time to see all three cities. Just for reference the RS tour that covers the same cities stays 3 nights in each. Even then they just cover the highlights. With 5 nights you may want to concentrate on one city, perhaps Rome.

Skip Greece and spend all of your limited time in Italy.

Pick 2 cities. Your trip should not be a mad dash of 4 major cities in 7 nights.

This is your honeymoon, right? On my honeymoon I wouldn't be doing so much moving around. I'd want to visit special and romantic places and spend some time there. This way the most romantic thing you will see will be the inside of airplanes and trains.

I would go with the "skip Athens and do 2 cities" suggestion. But if you "must" do Athens then I would suggest that you you do Venice (2 nights), Rome (3 nights with a day trip to Florence) and Athens (2 nights). Or maybe just Rome and Athens. You will loose 1/2 day when you move cities so the less you move the better. Congrats and have fun.

Skip Greece and spend all of your limited time in Italy. Pick 2
cities. Your trip should not be a made dash of 4 major cities in 7
nights.

I'll second this. Even adding the 2 Athens nights to Italy gives you very little time to do justice to Rome, Florence and Venice. With just 7 nights - and I assume one of them is your arrival day from India - I would choose just two of the three Italian cities, flying into one and out of the other. Rome, IMHO, needs a minimum of 3.5 days/4 nights just to scratch the surface, and you will lose at least 1/2 day to the transfer process every time you change cities.

If still insistent upon 3 cities, scrap Athens and:
Fly into Rome: 3 nights/2.5 days
Train to Florence: 2 nights/1.5 days
Train to Venice: 2 nights/1.5 days
Fly home from Venice.

Or do it the other way around. 4 major cities in two countries over 7 nights would leave you seeing not much more than trains and airports, and even 3 cities in one country is too rushed, IMHO.

Flights often work better (so you aren't up in the middle of the night) if you fly into Venice and out of Rome. So many of the flights out of Venice are so early in the morning and because there is the lagoon between the islands of Venice and the airport it can be inconvenient in the early morning.

With 7 nights in Europe, I suggest that you pick 2 cities - Rome and Venice are the obvious choice, as you will spend less time in transit. Will you have jet lag? - that will slow you down.

Italy to Athens is going to take 7 hours door to door.

Suggest you pick ONE country.

If you are going to Athens, two nights is not enough. If you insist on doing Italy and Athens, then stick with Rome and add another day to Athens.

And remember if this honeymoon is immediately after the wedding, you will probably be exhausted from the wedding.

Pick one country or the other. Then pick a maximum of two bases for that small time frame. You are trying to do way too much. I would say Rome.

A lot of it is personal preference, but between Venice, Florence, and Rome, I'd skip Florence and do 2 nights Venice, 3 nights Rome. Florence we found to be crowded, disorganized, and not a lot to do if you don't like shopping or museums. I love, love, love Rome - there is so much to see and do! Venice is fun but very touristy but I do like it better than Florence.