We took a Sunday day trip 1.5 hours south, to Trifels castle (Kaiserburg Trifels), and were very pleased! The castle had just the right mix of natural scenery and history.
Located in the Southern part of the Palatinate Forest, between Landau and Pirmasens, Trifels is perched up on a sandstone rock formation called the Sonnenberg. Driving west on the B10 towards Annweiler, you can see the castle right away when you reach the town. We almost made the mistake of parking in town where the Burgstraße ends at a park with hiking trails leading up to the castle. This was a good choice to not park here!! It would have been a 500 foot and several mile hike to the top. Instead, we did some quick re-research and drove the 5 miles around the mountain formation and to the Barbarossa restaurant and parking area. Parking was 1.50€ but you get this refunded if you eat at the restaurant. We had a great German lunch at the restaurant, which was just what was needed after the drive. The menu was typical Pfalz with a few twists. For example, a mozzarella topped schnitzel variety. The ambiance was excellent with a fireplace going, and that same fireplace shaped like the castle which you can see a few hundred feet overhead.
From the parking lot it is a 15-20 minute, moderately steep walk up to the castle. Entry is 3€ per person but well worth it! Now for you castle traditionalists, you may not be quite as enamored, for much of the exterior has been redone in the 19th and 20th centuries. The original castle dates back to the 11th century and there is a nice set of models that show the castle then and now. You can walk throughout the castle and into the various rooms at you own pace. Highlights include the jail cell where Richard and Lionheart was kept after his capture coming back from the crusades. There is also a room with replicas of the jewels once kept on the castle from the Holy Roman Empire (crown, sword, specter, etc).
Each room has a book detailing the history. Finally, for those appreciating a view, there are three awesome vantage points where you can see for miles! On the South side you can literally step out onto an edge of a cliff, the red standstone formation the castle was built on.
What is so interesting to me about the landscape is now each mountain in this area stands alone, where in the Northern Palatinate it is mountain ridges. The landscape kept me thinking of how one would guard, or attack, such a place back in the day.
If you are looking for a nice few hours to spend, I highly recommend Trifels!