From the Introduction
This is another in a small series of capsule adventures. I designed these particular encounters to be sort of an “ongoing encounter haven” for a small group of adventurers craving some kind of afternoon diversion. The River can be visited many times without exhausting all of its possibilities. Other adventures could be made to springboard from several of the encounters herein.
The main story thread tied to The River is a search for the treasure of the Dread Pirate Roberts. In my campaign, the story developed like this: A newly created character was a slave to Peg Leg Larry—a notorious pirate marauding the local river and seacoast. As her first act, she strangled him with his own “soap-on-a-rope” while being forced to bathe him. Seizing the opportunity, she fled his ship with a sack full of navigational items, a few coins and his rather large and gaudy red pirate hat. After a few adventures, she and her new companions discovered a treasure map hidden inside the brim (see separate map). After several tries, the ancient treasure was uncovered but all did not go quite as well as planned (which led to other adventures; and so on, and so on, etc.).
Of course, how you decide to develop your story is entirely up to you. But you may find it useful to tie it all together with the treasure map and legend of the Dread Pirate Roberts.