Ajloun Castle is definitely worth a visit. This time we combined Ajloun with a trip to Umm Qais although you can easily combine it with Jerash since it is pretty close, or even do all three of them in one day from Amman, if you leave early and can’t get enough of stones.
Even the way is quiet interesting since you go up and down a few times until you climb up the hill where the castle is located. You have an excellent view over the area up to the Jordan Valley and the city of Salt in the far as well as Palestine.
The castle itself is nice and in good condition. So it is definitively more than just ruins and far more interesting than the desert castles for example. It is a great spot to take pictures. We went on a Friday in November and it was not very crowded either. Later we went on to Umm Qais, where I have been already twice before. On the way back from Umm Qais we took the Dead Sea Highway. When you take the turn towards Salt it is really nice especially around Sunset. There is also a cafe called “Cafe Sunset” with an excellent view over the Jordan Valley. You might consider a short stop there to enjoy the Sunset.