While we're on the subject of Lewis and Clark, have you ever been to St. Louis?
My wife, daughter, and I were on our way home, from a vacation visit to friends in Oklahoma, and stopped in St. Louis for the night. While exploring the city and while in the vicinity of the Arch AND quite by accident, discovered that there is an underground museum situated between the legs of the Arch. The museum is devoted entirely to the expedition of Lewis and Clark.
We spent the ENTIRE evening in there, completely amazed and very much impressed.
Check the link:
Museum of Westward Expansion