We did 2 day trips while in Syria. The 1st was to a Crusader Castle from 1031 called Crac Des Chevaliers just outside of the town Homs. We took a taxi to the bus station and were lead to an air conditioned bus to take us to Homs. Public transit is very very cheap, very reliable to larger towns, and really a fun way to travel. In Homs we hired a guide who took us to visit St George's Monastery and then the castle. The castle was huge, amazing to wander thru, and really well preserved.
Our 2nd day trip was to the ancient city of Palmyra dating back to the 1st and 2nd century AD. Palmyra is probably the most popular ruins site in Syria, and well worth the hassle of getting there. From Damascus it is about a 3-4hr bus ride into the middle of nowhere. The bus we took was filled with villagers, and Bedouins- we were the only tourists on it. The site of Palmyra is huge- and fairly well preserved. There is an Arabic Castle called "Qual'at ibrn Maan" that overlooks the ancient city, and offers amazing panoramas. The gate keeper to the castle gave us a free tour with his limited English- it mostly consisted of him pointing and saying one word descriptors like "sleep", "water", "bread", "boom boom boom." Not entirely sure whether he was referring to cannons or hanky panky for the last one. I prefer to think that he was pointing out the shagging room! Here are some photos from Palmyra: