Suggestion on a side trip

Five cities in 17 days doesn't give you time for any kind of side trip. In fact you lose so much time every time you change cities that you'll have only two days per city. You should cut this back to three cities and that would give you time for a side trip.

Agree with previous poster. Too many cities for 17 days. Consider going with Paris, Amsterdam and adding Brussels, Bruges and Versailles near Paris OR going with Prague, Vienna and Budapest, perhaps adding Salzburg, Austria.

There are dozens of nice day trips to be made or, even better, stops in between. If indeed you had the time for it...
Limit yourself to Prague, Vienna and Budapest, which are only four hours from each other by frequent trains. Have three days for each city itself, and two days for day-trips or an intermediate stop. Tabor is a wonderful day-trip from Prague, and between Prague and Vienna you could have a night in Brno. From Vienna the baroque monastery of Melk is a worthwhile day out, and between Vienna and Budapest you could stay one or two nights in Györ.

Cesky Krumlov lies between Prague and Vienna. It's beautiful, but has become a bit touristy. Gyor and the Archanbey at Pannonhalma lies between Vienna and Budapest. Gyor isn't a village, but the old town feels small and quaint. Szentendre and Vac, both 30 minutes outside of Budapest are relaxing and charming.

I would split this trip and do Paris, Amsterdam and one other stop one trip and Prague, Vienna, Budapest on another trip. You will get a lot more bang for your buck and have time for a couple smaller places on each trip.

Have to agree with the others. For the large European capitals that you mention you need at least 3 full days in each (preferable more) plus travel time between them. You need to either increase your number of days or reduce your destinations. With 17 days for the cities you suggest I would eliminate Prague. That would give you 3-4 days in each of the others with ample travel time between them. Fly into Paris and out of Budapest or vice versa. If you want to throw in a quiet town between these that is convenient to transportation that could be done also by eliminating a day in one of the larger cities but would probably shortchange that city. If you need or want to fly round trip into and out of the same city, then you need to concentrate on either the west (Paris, Amsterdam, and another city or two nearby) or the east (Vienna, Prague, Budapest), just to make the logistics of getting back to your starting place easier.

Guidebooks for each city will cover the most practical side trips. In particular, Amsterdam has lots of train service to nearby smaller towns; see suggestions under Netherlands - At a Glance. From Budapest, trains and ferries both make easy day trips to the Danube Bend area; you could use a different route in each direction.

From Budapest, trains and ferries both make easy day trips to the
Danube Bend area

"EASY" is a depender.

Some Options:

A. Via Vac = 4 hours of travel time to see four very interesting towns. Figure another 2 hours of going back and forth to train stations and an average of 2 hours per stop if you want to do the trip justice. So that’s 14 hours out of the day. Great in the summer when there are long days.

Train from Budapest (Nyugati) to Vác: <45 minutes
Train from Vác to Štúrovo / Esztergom: <45 minutes
Bus (880) from Esztergom to Visegrád: <60 minutes
Bus from Visegrád to Szentendre: <45 minutes
HEV from Szentendre Budapest-Batthyány Tér <45 minutes

B. Direct to Esztergom = 4 hours of travel time plus about 1.5 hours of back and forth to the train station and an average of 2 hours at each stop = So 11.5 hours out of your day to see three very interesting towns. Another long day.

Train from Budapest (Nyugati) Esztergom: <90 minutes
Bus (880) from Esztergom to Visegrád: <60 minutes
Bus from Visegrád to Szentendre: <45 minutes
HEV from Szentendre Budapest-Batthyány Tér <45 minutes

C. Just Szentendre < 90 minutes of travel time plus about 1 hour going back and forth to the train station and 2 hours in town or 4.5 hours or a nice afternoon trip.

Train to Szentendre and back: <90 minutes round trip.

D. Just Esztergom. Well worth a solitary trip. <180 minutes round trip, 1 hour back and forth to the train station and 2 hours of visiting (maybe more). So 6 hours for a good full day trip.

E. While there is no train between Visegrad and Esztergom, there is a train between Visegrad and Budapest. So Pairing Esztergom and Visegrad also works as does paring Szentendre and Visegrad. Figure an eight hour trip for either…….

To sweeten the trip, take the boat back into Budapest from Szentendre. For that add about 15 minutes more to the total time. Its bigger travel difference but because the boat docks right in the heart of the old town it’s not much longer than walking back to the train station and riding the faster train home. And it’s a lot more fun and beautiful when entering Budapest on the water.

With the time frame you have, I strongly suggest cutting back to the three cities that really holds you strongest interest. The rational for this suggestion is that moving from one place to another almost always eats up more time than anticipated. It includes packing up time, checking out, getting to the train station /airport, the train / plane time itself, finding the new hotel, and then checking in and unpacking. I'm sure you want memories of things other than train stations, airports, and taxi rides. Don't mean to rain on your parade, just food for thought.

Thank you all for the suggestions!

I am likely going to Vienna-Salzburg-Budapest-Prague with side trips/stopovers for this time :)

Considering logistics, I'd suggest this routing ...
Start in Budapest (5N)
Train to Vienna (4N)
Train to Salzburg (2N)
Bus to Cesky Krumlov (2N)
Bus to Prague (4N)

I am saving big if i do a round trip to Vienna. So I am thinking - Vienna - Salsburg - Cesky Krumlov - Prague - Brno-Budapest -Vienna and back home. I am trying not to go over 3+ hours of train journey at any point since i have a 1 year old travelling with me :). Would you have any alternate suggestions?

since i have a 1 year old travelling with me

In journalism, that's called "burying the lede."

With a 1 year old, you REALLY have to think about scaling down both the number of destinations and what you can see in them. With a child who needs feeding, diaper changing, etc., you simply can't run around as you can on your own.