This June, our group of 4 adults plan to visit Munich and Fussen coming from Salzburg then leave for Interlaken, and finally flying out from Zurich. We like the idea of having a car for our day around the Fussen area. Would it make sense to rent a car after seeing Munich to use in Fussen and then dropping it off somewhere near the Swiss border before traveling by train to Interlaken?
You say that you are coming from Salzburg and then want to visit Munich and Fussen.
How will you get to Salzburg? It seems unlikely that you will fly into that city. Why not fly into Munich, then take the train to Salzburg then head toward Garmish and Fussen. You can rent a car, suggest after you see Munich.
Not sure about dropping it off near the border. If you rented in Austria, you could drop it in Innsbruck. I do know that some rentals charge a lot extra for dropping in another country.
We are flying into Vienna first then will take train to Salzburg.
If you can return it in Germany, then it makes sense. Depending on your Munich plans, it might make sense to rent in Salzburg or even Vienna and return it in Austria perhaps in Innsbruck or maybe Feldkirch ( on the Liechtenstein birder )