First Trip 21 days

You could barely do justice to any one of those countries in 3 weeks, let alone 3 very different ones. Perhaps start by letting us know which cities or areas you are most interested in seeing, and what types of sites or activities you want to see/do. And bear in mind that given the distances involved, every travel day will result in a loss of a sightseeing day. So you wont have 21 sightseeing days on your trip. You'll may only have only 17 if those 21 days include your transatlantic flights.

I agree. The goal is to enjoy yourselves on a comfortably-paced trip, not to see the most countries possible.

"Most" of your time, if you have 21 days, would mean at least 11 days in Italy. That leaves 10. I think 10 days might be alright for Germany. You could maybe visit 3 different places max in Germany. Rick Steves provides very questionable guidance for 10 days of independent travel HERE. It's way too rushed. I would subvert his suggestions as follows.

• Arrive FRA airport; spend 3 nights in the Middle Rhine Valley. It's roughly 1 hour by train from the airport. Take a day cruise, tour some castles, enjoy the wine and the vibe.

• Train to MUNICH, spend 4 nights. Do a day trip to Salzburg.

• Train to Garmisch-Partenkirchen (base town in the Alps,) spend 3 nights. Day trip to nearby Mittenwald. Many things to choose from here.

Then head into Italy. G-P > Innsbruck > Verona/Venice. It's a beautiful train ride indeed.

If nothing else, plan to fly into somewhere in Italy, then advance north methodically until you reach a departure point (or vice-versa). Flying into, and out of, northern Europe then visiting Italy requires a giant loop.

Do you plan to travel by train, car, or plane in Europe? 5 adults may be tough in one car (yes, you can rent bigger cars, but bigger cars don't 'fit well' in Europe). Train travel can be delightful in Europe.

Try to purge the idea of 'seeing the most number of countries'. By the time you are done, you'll be sick and tired of seeing anything if you aren't careful (and you won't remember what you saw in the beginning!). On our first major trip to Europe, 30 years ago, we visited Germany, Austria, Italy, and we felt that was too much.

These days we do about 3 major international trips a year, and try to focus on just one region or country. If at all possible, think of this as just the first of many visits, and narrow your focus. I will say that our last trip - which was almost exclusively to Switzerland (we did fly into Milan) - provided an amazing amount of variety given the German, French, and Italian 'zones' .

We can fly into either England or Germany and want to spend most of our time in Italy.

Can you fly home from Italy? Besides the itinerary suggested by Russ, you could go through Switzerland to get to Italy.

Thank you everyone!
We are thinking of staying in Frankfurt for 3 nights then heading to Florence by train. We don't mind the travelling by train for the day. Then choosing other places to stay in Italy. Welcome suggestions for other places to visit besides Florence and Venice or Rome.

We are thinking of staying in Frankfurt for 3 nights

An unusual choice. A weak one too unless seeing Germany just isn't important. I don't know of any travel authority or anyone else who names Frankfurt as the one place you must see if you set foot in Germany. And since you will be taking the train to Italy anyway... why not make some PROGRESS toward Italy upon arrival? It's only 2 hours from FRA airport to Freiburg (near the Swiss border) by train. It's a city your train to Florence would surely pass through anyway, and it's an especially nice one to spend some time in, IME, a great place to wander. And if you have the inclination, a short, scenic rail trip from there - one of Germany's more famous train routes - makes for easy access to the nearby Black Forest towns.

https://visit.freiburg.de/en/discover/sightseeing/old-town

https://www.black-forest-travel.com/landscape/hoellental.html

okay, Great! Thanks for the advice I will look that up now!

Map of that railway into the Black Forest with town names:

https://commons.wikimedia.org/wiki/Category:H%C3%B6llentalbahn#/media/File:Verlaufskarte_H%C3%B6llentalbahn_2.png

Frankfurt am Main isn't an ugly or bad place, but as already mentioned, you don't need to stay there for more than a day unless you use it as a base camp to travel to other nearby places by train.
I'd opt for Italy, Austria, and the Czech Republic, in addition to Germany.

I think there's a sort of philosophical issue here that should be addressed before making an actual itinerary. Many people like the fast-paced check-the-box sort of travel, and they pride themselves on the number of highlight destinations they visit on a trip. At the other end of the spectrum are the folks who want to explore fewer areas at a much slower pace and whose goal is to feel they have a deeper understanding of a region's culture and history. For many people there is the added sense that they may only have one opportunity to visit Europe and they want to see as much as possible.

I don't believe there is a right or wrong way to travel, but I think it helps to have some clarity on what your goals are for a trip. There are also practical issues. I suspect most readers on this forum would agree that a fast-paced trip with frequent changes of accommodation and frequent travel (particularly long distance travel) is both more expensive and more tiring. Perhaps you and the other 4 adults in your group could discuss what you each really want from this trip. Having 21 days in the spring time for a vacation sounds fantastic and I hope you can come to some agreement about what kind of trip you want to plan.

Hard to beat the below.

If it's too much for you, pick and choose what suits your group best.

You'll have a great time!

I'd suggest you study various Rick Steves recommended itineraries for ideas and see what resonates.

Happy travels.

https://www.ricksteves.com/tours/europe/europe-21-days

Best of Europe in 21 Days Tour

Day 1: Welcome to the Netherlands Sleep in Haarlem.

Day 2: Progressive, Artistic Amsterdam Sleep in Haarlem.

Day 3: Dutch Treats and Rhine Views Sleep in Bacharach.

Day 4: Rhine Castles and a River Cruise St. Goar, we'll hike up the
hill to tour the mighty medieval Rheinfels Castle and enjoy its
commanding view of the Rhine Valley. Rhine River cruise Sleep in
Bacharach.

Day 5: Medieval Rothenburg Sleep in Rothenburg.

Day 6: Dachau and Salzburg

Sleep in Salzburg.

Day 7: Salzburg and Strudel

Sleep in Salzburg.

Day 8: Italy's Incomparable Venice

Day 9: The Art of Wandering in Venice

Day 10: Florence and Michelangelo's David

Day 11: Wonders of Renaissance Florence

Day 12: All Roads Lead to Rome

Day 13: A Walk Through Caesar's Rome

Day 14: To Italy's Cinque Terre

Day 15: Free Day in the Cinque Terre

Day 16: To the Heart of the Swiss Alps Sleep in the Lauterbrunnen
Valley.

Day 17: Free Day in the Alps

Day 18: A Hearty Taste of Burgundy Sleep in Beaune.

Day 19: Historic and Neighborhood Paris

Day 20: Parisian Cityscapes and Masterpieces