On your way from Berlin to Prague your train will stop first in Dresden and afterwards in Bad Schandau (the last german stop). I second to stop atleast for few hours here. Bad Schandau and Saxon Switzerland offer some nice nature spots and even the railfan have something to explore.

The main tourist attraction in Saxon Switzerland is ofcourse the  Prebish Gate or the Bastei with a beautifull view on the valley of the River Elbe but i will show you my secret spot that is till yet not so crowded as the “Bastei” and the village Rathen.
From Bad Schandau goes a tram that use pretty old Tramcars to the Lichtenhainer Waterfall from here it´s a short walk to the “Kuhstall” (cowhed). You work up to a hill and it can be exhausting but the view you will get worths the effort.

Thanks to @runner.on.rails  for the pictures.

For me as fan of transportation like ofcourse the old tram from Bad Schandau to Lichtenhainer Waterfall. Another village i like to visit is Rathen (rechable by the S-Bahn in the Elbevalley Interrail/Eurail valid or by steamship of the Elbe Ship Company). Rathen is famous for the near Bastei (Did you know that next to the “Bastei” also a “small Bastei” exists) and the Open Air Stage with shows of Karl May stories. For me more interresting is the ferry on the Elbe that works without any engine as it use the flow of the River to cross it.

For the kids there is a outdoor model park with a small pension if you wanna extend you stay in the Elbe valley.

Ofcourse there are even more to explore in Saxon Switzerland (for example Königsstein) but this would make this post even bigger. To find informations i recommend to visit the  offical website of the region https://www.saechsische-schweiz.de/en/ Here you can find many Informations about What to do. Where to stay. How to get there and many many more.