Historical clue formulations

• Drifted downriver, say — 2021-01-27
• Traveled with Huck Finn, e.g. — 2010-10-11
• Traveled the Yellowstone River — 1999-12-31
• Floated down a river — 1995-06-26
• Dared the white water — 1995-06-10
• Traveled à la Heyerdahl — 1995-02-26