This site shows you the best route to the hotel Seelust, click on "Calculate Route".
Coming from the south i.e. Hamburg direction you will be on the E3/A7. Leave at the exit "Büdelsdorf" for Eckernförde, B203 and carry on through the city of Eckernförde. Follow the signs for the HOTEL SEELUST in the city.
Hotel Seelust***garni
Preußerstraße 3
24340 Eckernförde