To get back, you just follow the same trail down. You can spend at much time as you want exploring the park and different trails, but always keep in mind the time for the last ferry ride back to town. You will be stuck like chuck if you miss it since there are no footpaths that lead back to Schonau am Konigsee. But if you’re going to be stuck somewhere, this is a pretty good place to be.
If you’re going to be in Salzburg (or Munich even) and need a day trip idea, definitely head over to Lake Konigssee. Not only is the lake gorgeous (post coming soon) but this hike will take your breath away. While the area around St. Bartholomew’s Church can get its fair share of tourists, once you start exploring around the lake and park, it is extremely peaceful. While out, I only ran into other hikers a couple of times the whole day. For the most part, you feel like you have the whole park to yourself, it’s a pretty cool feeling.