By car ...  
... from Zürich A 1 direction Bern
... from Bern A 1 direction Zürich
... from Basel

A 2 direction Luzern, then A 1 direction Zürich

... from Luzern A 2 direction Basel, then A 1 direction Bern
Exit Rothrist, drive direction Aarburg/Olten, in Aarburg direction Olten. The Gasthaus Bären is on your right-hand side in the old center of Aarburg.
   
By train  
Take the train to Olten, then the Bus to Aarburg, bus stop "Städtli", Bus 2, for timetable click here