The apartment was lovely. It is in a quite neighborhood with shops, restaurants, and the transit all near by. Katharina was nice to meet us even though we came in a bit late. She provided helpful restaurant recommendations with nice thoughts on life in Munich.
The apartment is easy to reach from the airport. Follow S signs to the train. Take either the S1 or S8...but I think S8 is a little shorter. Validate the ticket before getting on the train. Get off at Ostbahnhof station. Maps are clearly marked on the train for stops. You can get 1-day or multiple day tickets. I recommend the trams/buses for moving around Munich. A 1 day ticket works for the day and night after validation. It expires at 6AM the next day.
Tickets outside Munich seem easy to purchase. Those are different.