In 1 hour drive from Bad Reichenhall in the gorge the castle Burg Klammstein is situated.
The address for the navigator:
As far as I understand, there is a small hotel and restaurant in the castle. You can walk around the castle grounds, or visit a small Museum that tells about the chivalrous history of the Gastein district.
Now the castle works on Sundays from 11 until 16 o'clock, the excursions are held every hour. However, i haven't found the information about the cost of the visit. Reviews on Google advise you to stay in this castle when moving from one attraction to another. The castle is small and very suitable for such a short stop, when you can take a break, have a snack in the local tavern and get acquainted with the small Museum located in the castle tower.