my last CouchSurfer in May disliked Salzburg, so i would not recommend it even so i like it 😉
If you like nature&hiking, you can make a nice day trip (buy a cheap day ticket!) with BOB ( www.bayerischeoberlandbahn.de/ ) to Schliersee, but only when the weather is good! And you should have hiking shoes as well. There are some other nice areas around Munich (i.e. also Starnbeger See), but you won’t stay to long, so you have to focus.
My plan (in your case) would be:
– Schloss Nymphenburg and Park (Tram 17 from central Station/Hauptbahnhof)
– www.pinakothek.de/pinakothek-der-moderne – modern art museum, on Sundays only 1 Euro entry fee! There are other museums (with „old“ art closeby)
– Center of Munich + Viktualienmarkt (local market place in the center)
– „Alter Peter“ tower in the center of Munich (great view! en.wikipedia.org/wiki/St._Peter%27s_Church_%28Munich%29 )
– Oktoberfest (if you have never been there, otherwise…. 😉
– Olympia Tower (great view on the Oktoberfest on the evenings, but cold during this time), BMW Welt and maybe BMW museum (also close to eachother)
Enjoy your stay….