From Dublin, follow the N81 out of the city, pass through Blessington in the direction of Baltinglass, taking the turn for Knockanarrigan (Glen of Imaal). Follow this road until you reach a shop with petrol pumps and a pub called the Glen Lounge. Take a right turn between the pub and shop.
Then take the next right at a fork in the road and the following left at the next fork. Continue on this narrow track-like road for mile and half until you see the Gasthof on the right hand side (It can be a difficult place to find, but don't give up until you get there.)