If you do decide to travel by car:
From Munich – Salzburg: via A1 – exit Thalgau and via Hof, Fuschl, St. Gilgen, Strobl to St. Wolfgang.
From Vienna – Linz: via A1 – exit Regau and via Gmunden, Ebensee, Bad Ischl, Strobl to St. Wolfgang.
From Graz: via the A9 – exit Liezen and via Stainach Irdning, Bad Mitterndorf, Bad Aussee, Bad Ischl, Stobl to St. Wolfgang.