A preliminary itinerary that we could comment on would make it easier, or at least, what are your interests, nature/history/castles/cities/etc?
Of course Budapest can be included, but since it's not exactly on the standard route between Warsaw and Prague, I'd advise against it. You probably don't want to spend too much time en route with a toddler.
My suggestion for a general plan would be to go to Wrocław (by train) after spending some time in Warsaw, spend a couple of days there, then see the Książ Castle in Wałbrzych and spend several days around Szklarska Poręba/Karpacz to enjoy some nature in the Karkonosze National Park (maybe rent a car in Wrocław to make it easier) and then go to Prague by bus (4 hours from Wrocław).
Alternatively, skip the Karkonosze NP, go straight to Prague from Wrocław and rent a car there instead in order to go to Bohemian Switzerland.
So if i read this correctly, warsaw > wroclaw>prague>Bohemian and back to Prague?
Can i include cesky Krumlov?
Warsaw 2days, wroclaw 3 days, prague 3 days, bohemian 1 day.
Do i need to alter this?
Can i also squeeze in krakow? Is it worth?
Finally, is October a good time?
Sorry to bombard you with ao many questions. Thank you for answering.
Yes. And renting a car in Prague so that you don't drive your rental car across the border.
This sounds like a good plan, I would only change it to spend one night in Bohemian Switzerland and cut one night from Wrocław.
Český Krumlov would make it a bit more complicated since it's in the opposite direction from Prague, so I'd say skip it because 1) it's better to take your time to enjoy the beautiful nature in Bohemian Switzerland and 2) your kid probably won't appreciate spending too much time driving around.
And the same with Kraków. Since it's out of the way, you'd have to cut some time from other places. You can visit Kraków instead of Wrocław though, but in my personal opinion Wrocław is much more worth visiting.
The beginning of October should be good, Polish/Czech autumn can be pretty then, but of course nobody can predict the weather.