Microbuses leave from Lattakia to Al Haffa regularly, Al Haffa being the village on the way to Qala'at Salah Ed-Din. Taking a taxi or a shared private microbus is also possible but I do not know the price. It is obviously negotiable. The road is crowded with vehicles of every sort since the area is an agricultural one and the road is narrow and winding.
From Al Haffa to the Castle my friend and I took a motorbike taxi. This is absolutely unrecommended! The road from Al Haffa to the Castle is narrow and winding and downright perilous. At one point is passes over a bridge without railings, with cars and other vehicles occasionally coming the opposite way. To make matters worse, being the lightest of the three, I had to sit at the back with nowhere to put my feet except splayed out and the weight of the other two squeezing the breath out of me. After this ride I lost sensation in certain parts of the body! Needless to say crash helmets were non-existent. Moreover, the motorbike driver lacked good manners. We took a more comfortable taxi on the way back and next time I go to this splendid castle, I'll take a (car) taxi or rent my own car.
1 - the road to and from the Castle. See transportation tip.
2 - Sheer height. Some areas such as roofs and stairs are not protected by railings and are not places for those who cannot stand heights.
3 - Heat and dehydration. Stock well on water bottles and protective clothing especially in summer.