At the roundabout (next to huge supermarket "INTERSPAR"), take the exit to Kritzendorf/Höflein. (Ignore the "road blocked" sign: The road is blocked after Höflein; before Greifenstein.)
Drive through Kritzendorf. Take the first possibility after the place-name sign "Höflein" to turn right (there is a green arrow "Strandburg Silbersee"). Attention: This is a switchback!
Cross the rail tracks and drive straight ahead towards the riverside of the Donau (Danube).
Turn left when you reach the boardwalk ("Treppelweg"): You are already in "Donaulände"!
When you face the traffic sign "no vehicles", turn left and park your vehicle on the property (parking at the river bank is possible, but prohibited).
Drive carefully: A lot of bicyclists and pedestrians use the "Treppelweg"!
Here is a sketch of the route:
Go to the the river bank and then downstream for about 800 metres.
Here is a sketch of the route: