Nymphenburg castle (within city limits) and its grounds are beautiful in September/October. A hike through the
Olympic Park with its artificial hills provides a great view of the city plus you can stop by Munich's highest beer garden, the Olympia-Alm. Take the S-Bahn to
Dachau to tour the Concentration Camp (if you can take it) and the Old Town, have your afternoon coffee and mouth-watering cake on the castle terrace. Or go south to
Lake Starnberg. All of these are accessible on public transport so any residue alcohol after last night's binge shouldn't stop you.