Rhein River, Germany - Ruin Fürstenberg to Berg Schönburg

Ruin Fürstenberg - Built by order from the archbishop of Cologne to provide protection and levy tolls. It is privately owned and there are no tours.

 Bacharach, a town on the river.

Berg Stahleck - Built on orders of the archbishop of Cologne, it was destroyed in the late 17th century and rebuilt in the 20th.  It is now a hostel.  https://en.wikipedia.org/wiki/Stahleck_Castle

 Town of Bacharach.  https://en.wikipedia.org/wiki/Bacharach

 Toll Station Pfalzgrafenstein.  Built by Ludwig the Bavarian.  Take a river ferry trip and get a guided tour once you are there.  http://www.loreley-info.com/eng/rhein-rhine/castles/pfalzgrafenstein.php

 Burg Gutenfels on the top of the hill is not open to visitors but it is a hotel.  The town along the river is Kaub.

 This shows the Gutenfels on the hill and the toll station in the river.

 Berg Schönburg sits on top of the hill.  No visitors but it is a hotel.  Ferdinand Freiligraph once said that it is "the most beautiful refuge of the Rhine Romanticism."  A hiking path is available from here to Oberwesel.

Oberwesel is considered an impressive evidence of town construction in the Middle Ages.  You can see 16 military towers and an accessible city wall.  For reference, Burg Shöenberg is on the top of the hill on the left (first photo below).