My wife and I will be in Munich for 2,5 days in February and was trying to work out what train ticket to buy. I will need:
1. tickets from the airport (MUC) to the Hauptbahnhof on the first day;
2. tickets from Hauptbahnhof to Garmisch-Partenkirchen on the second day; and
3. tickets from Hauptbahnhof to the airport (MUC) on the last day (morning)
Can anyone advise what ticket(s) are best to purchase for two people travelling together?

Thanks in advance