Tarpon Springs is up a river from the Gulf. It is a great experience when you get to the town area (about 3 miles up the river) to be surrounded by commercial fishing boats, sponge diving boats, etc. Real character. At the end of the run is the small city run marina. Reasonable rates but best to call in advance to reserve a slip. Within walking distance of all the great Greek restaurants and typical tourist shops. Don''t miss it.
Trip up the river is straight forward. Just watch the markers and have a chart available to refer to to avoid making a wrong turn which will lead you to very shoal waters. Not a difficult problem.