Slovenia

I found driving in Slovenia to be quite easy and didn't have trouble finding hotels in Ljubljana and Lake Bled that had parking.

In Ljubljana, I stayed and parked at the Grand Hotel Union, which is right in the tourist center.

At Lake Bled I stayed at the Old Bled House, which had parking and was a short walk to the lake.

I see that someone has already given you the information - in another post - that you'll need a Vignette on your car. When I rented in Croatia, as I think I read that you're doing, the rental car did not come with the Slovenian vignette.

I found driving in Slovenia super easy, too. I dropped my car off in Ljubljana, so I didn't have to park there, but just parked at my lodging at outlying sites.