In Munich, if you stay near the train station (Aloft and Le Meridien) you can rent a car at the train station. That way, you can do public transport until time to leave. And IIRC, you can take the Ubahn to BMW World right from there. Drop it off in STR at the train station and back to public transport.

ETA::
The Deutsches Museum has a separate transport museum that has cars and buses in Munich. https://www.deutsches-museum.de/verkehrszentrum/
Also, go to English Gardens and watch the surfers