Crac des Chevaliers, Homs, Hama, Apamea
Central Syria offers a wide variety of places to visit. With an early start, each of them are possible in a day trip from Damascus, but if you are planning more than 4 hours in each, the long distances make this difficult. It is definitely possible to visit Crac des Chevaliers this way, but either of the main cities, especially Hama, deserves more of your time. That being said, Crac des Chevaliers is indisputably Syria's main draw for many tourists. Hama is graced with a wonderful old city and some of the finest and largest waterwheels around. Homs is a more modern place with no traditional attractions but its main mosque and famous sweets (the helwayat jubneh), and Apamea's decumanus outdoes Palmyra's.
Crac des Chevaliers (Qala'at al-Hosn)
This crusader castle most definitely deserves its label as the most spectacular in all the world. Having been to quite a number of them, I can attest to the veracity of this claim. In fact, no other really even comes close. Not only is it absolutely enormous, but most of it is not even in ruin. The only thing it is missing these days is being lit up at night. You can literally spend hours going from chamber to chamber and finding new and dark corners to explore. The ticket office is on the lowest end of the castle, from which you scale upwards and can eventually reach each of the turrets. It is worth both exploring as many nooks and crannies inside as possible (especially the towers which allow you to get a better bird's eye view of the greater structure) as well as heading outside and walking up the road to see the castle from afar. The architectural styles inside various depending on which part of the castle you are currently in - whether it is the stables, the church (now a mosque) or a wonderful section with 7 carved windows which in an odd way reminds one of being back in England and walking around one of the old Cambridge or Oxford Colleges.
Another one of the Crac's qualities is its beautiful location in some of Southern Syria's most fertile areas, offering fresh air and great views all around!
For me Homs has always just been a transit location from which I head to various other sights. As such, I do not know too much about the city. Most Syrians poke fun at the people fun for not being as clever as those from other regions, though soon the humour of this is lost on you as it becomes clear this is a stereotype left from years long gone. Still, if someone asks you if you are Homsi, this is meant as naught but an insult. Apart from its people, the city is known for two things: the Khaled ibn-Walid Mosque and the Helwayat Jubneh (Cheese Sweet).
Though its tragic recent past reduced much of the city to rubble, this place still offers several of Syria's most unique sights. There are still large sections of its immense Old City remaining, which offers a large souq (market) and many fancy handicraft shops. The real attraction, however, is its numerous Norias (Waterwheels). I suggest spending some time sitting in a restaurant by the Orontes River overlooking some of these huge and still-functioning structures (The Restaurant by the Four Norias of Becheriyyat might be a good starting point), and not to just see one and be done with it. If you do just see one, however, the two Norias adjacent to the old mosque in the city centre should be your best pick (pictured below).
Links to other entries
If you are interested in knowing more about other places to visit in Syria, I have several other blog entries covering other regions.
All of Syria: http://espen-lutken.travellerspoint.com/
Part I - Damascus and Introduction to the Country: http://espen-lutken.travellerspoint.com/3/
Part II - The South (Bosra, ...): http://espen-lutken.travellerspoint.com/4/
Part III - Damascus Countryside (Ma'aloula, Seydnayya, Deir Mar Musa, Bloudan, ...): http://espen-lutken.travellerspoint.com/5/
Part IV - The Road to Palmyra (Tadmor): http://espen-lutken.travellerspoint.com/6/
Part V - Central Syria (Crac des Chevaliers, Homs, Hama, ...): http://espen-lutken.travellerspoint.com/7/
Part VI - Aleppo Governorate (Syria's Second Capital): http://espen-lutken.travellerspoint.com/8/
Part VII - Euphrates Pt. 1 (Deir Ez-Zor Governorate): http://espen-lutken.travellerspoint.com/9/
Part VIII - Meditarranean Coast (Latakia, Tartous,...): http://espen-lutken.travellerspoint.com/10/