Just returned from our 10th Star Clipper sailing on the Star Flyer. They do not post port times. Even when you get on the ship, port times are not stated in advance. Once on board, at least on the Star Flyer, the best way to figure it out is to check the massage schedule in the Library. It had the port times on it so people would know when to schedule a massage. Also, check the excursion book in the library.
Doing third party excursions is kind of shaky, due to factors listed in above post. If you do book third parties, know the companies' cancellation policies. This past cruise , we had a tender that wouldn't lock for lifting for quite awhile before being fixed, and a big boat show in one port that required us to tender from pretty far out instead of docking.