Itinerary Prague Austria Slovenia Munich in May

My only suggestion is to use Google Maps to review your route and determine if the order in which you plan to visit these locations is optimal for you. You start relatively close to Munich (Salzburg) and then do go southwest, then southeast, north, and then back west again. You may be able to save yourselves a few hours of windshield time.

Best route:

Prague - Salzburg - Bad Ischl - Rattenberg - Salzburg (pick up car) - Lake Bohinj - Salzburg (return car) - Munich

All by train, except when noted.

We did a similar trip a few years ago. In my opinion you're really underestimating how much time it takes to move between those destinations. It's just a lot of time moving around; especially with such geographically spread out places. They aren't naturally well connected and the road system isn't like we have in MN.

Slovenia is great, but with your itinerary and your schedule, I don't understand how it makes sense. The alpine lakes and quaint vilaages you're going to see are all available much closer to Salzburg.

So maybe add some days, rejigger your stops or choose either Austria or Slovenia - You could even investigate a Prague-Slovenia open jaws.

They aren't naturally well connected ...

The towns are very well connected by train.

... and the road system isn't like we have in MN.

That is true. The roads may be not so wide, but they are in a much better condition than in US.
The trip between Salzburg and Slovenia is about 3½ hours, 90% of which on Autobahn (toll vignette required for both Austria and Slovenia).

As wmt1 has noted, dropping the car off in Salzburg instead of Munich is the optimal
strategy, as you won't incur a dropoff charge (which can be substantial) for renting in
one country and returning in another. Train from Salzburg to Munich is easy and
inexpensive.

Thank you to all who have replied. I have had fascinating conversation with CHAT GPT, guiding me to the proposed itinerary, arguing that the beauty of it is that there is no back tracking, all is forward movement, intentionally, zig zagging across the different areas of the alps. The cross-country rental fees are definitely acknowledged as a negative. I've had reservations, thus came here for input and I thank you for what was provided. I'll regroup.

Please let us know the itinerary you have eventually chosen.

I would take anything Chat GPT tells you with a grain of salt. Verify separately.