East european visit by car [closed]

Next days we're planning some visits starting in Romania and going to Italy by car. The route is: Romania - Hungary - Croatia - Slovenia - Italy (and back).

What things should we be aware of?

As far as I can tell, in Hungary we need a vignette (can be bought online here: https://ematrica.nemzetiutdij.hu/).

Croatia - only highway taxes apply.

Slovenia - we need a vignette, but it is not available online, right? And we need to place the sticker on the windscreen of the car (is there a required/recommended place on the windscreen?) Will we find the vignette at the border of Slovenia or before it, in Croatia?

Italy - only highway tolls.

I think the validity periods of the vignettes will not be a problem since we're staying 9 days, and the hungarian vignette is available for 10 days.

We're planning to stop in Italy, Slovenia and Croatia. Money-wise we're covered if we have Euros in Italy and Slovenia, for Croatia I understand that we can easily pay by card everywhere, and if not we can change euros for kunas, right?

All countries are in the EU, so I expect no problems at the borders.

Advice, things to be aware of?