The Citadel of Tartus is not a neat ruin with a ticket office. It is part of the old urban fabric, with surviving Crusader walls and later houses folded into the same quarter. That makes it harder to read, but more atmospheric than a cleared archaeological site.
Walk slowly through the lanes around the old city and look for the heavy blocks and changes in masonry. The reward is less about one viewpoint and more about seeing how medieval stonework has been absorbed into a living town.