Have fun. Dreher is the good beer in Budapest and Ottakringer is good in Vienna. You're on your own in Bratislava...never went there. Check out St. Stephen's in Vienna, plenty of street musicians in the square, if you're lucky one will be a ukist.
As much as I like the ukulele, which I’m certain is less than most people here, I think there’s time for uke and time to enjoy a place like Vienna (10/10) and not less Budapest (haven’t been to Bratislava). A lot to see in both cities, the uke won’t be mad if it’s left alone for a few days.
That’s unless you’re trying to find a ukulele player to take you around the city