You can get there from Vienna using the S-Bahn.
Once you are in the Center at the '''Marktplatz''' you can easily get to every remarkable spot by foot. The walking distances are quite short as Perchtoldsdorf is quite small.
Interesting spots in Perchtoldsdorf are the '''Wehrturm''' and the '''Rathaus''' (both 15th century) directly at the '''Marktplatz''', and the '''Pfarrkirche''' (church from the 13th century) and '''Herzogsbrug''' (castle from the 11th century) both in 2 minuite walking distance from the Marktplatz.