We took this picture of the Stolzenfels Castle. You can see it up the hill behind the Koblenz train station. It was recommended that we go see it, as it was rebuilt in mid 1800's after being destroyed by the French in 1689. This castle complete with furnishings, etc. is quite different than the ruins we saw later in the day at Rheinfels.
However, when we drove to Stolzenfels, five km's south of Koblenz, we found out the castle was closed to tourists every Monday (and this is just after the tourist info in Koblenz told us to go there -- lousy help for tourists). To reach the castle, you have to climb the hill about 10 minutes up from the water's (the Rhine's) edge.
Castle Stolzenfels is located just a couple of miles south of the Old Town, in the part of town known as Stolzenfels. Too far to walk, but a short taxi ride, train ride, or biciycle ride would get you there easily. When you leave Koblenz travelling south on the Rhine, this is actually the first castle that comes into view.
It was originally built in 1242 in response to the construction of Castle Lahnstein across the river, but in the 19th century it was converted into the opulent palace that it is today by the crown prince Frederick William IV, who later became the king. The castle was remodelled to suit the needs of the king who made the castle one of his residences, but it is said that actually never slept here. nonetheless, the castle is beautifully furnished, and is a real good castle to tour along with the Marksburg just downstream.
There is a nice write-up about Castle Stolzenfels at:
Tourists driving cars (their own or rented, as I did) should know that there are two roads, one on each bank of the Rhine river. But better choose left or right well before, because then you will very rarely have the chance to cross the river, as bridges are very few. I guess any side has the same beauty. I choose the right side (coming down from Koblenz to Mainz) because the main road is over here.
On the way, one can not stand not to pull off and take the pictures of the castles. Of course, the main attraction of the are the castles, Rhine Valley being somehow similar to Loire Valley in France.