I came across a little more information on one matter raised in this thread, the life and ultimate fate of Sacagawea:
A Difficult Start
Sacagawea was born around 1790. She was the daughter of a Shoshone chief. At about the age of 10, she was kidnapped by the Hidatsas during a raid against the Shoshones. Her father was killed. She then lived hundreds of miles away in a Hidatsa village on the upper Missouri where she was either sold or gambled away to Charbonneau, a French-Canadian trapper. As was custom in the Indian villages, Charbonneau had multiple wives.
When Lewis and Clark met Sacagawea, she was late in her pregnancy with her first child with Charbonneau. During the winter at Fort Mandan, she gave birth to a son, Jean Baptiste, who was nicknamed "Pomp" or "Pompey" by Clark for reasons that are not clear. The captains hired Charbonneau not only for his interpretation skills, but also for two advantages Sacagawea offered. First, the captains knew they would need someone to interpret with the Shoshones so that the expedition could buy horses from them to cross the Rockies. Second, having a woman and child was good public relations. It cemented the idea that this was a peaceful, scientific voyage.
The young woman was expected to pull her weight on the expedition. She did and then some. Her contributions gained her the respect of the captains over the course of the trip, judging by their journal entries. Early on, they referred to her as the "squar," or squaw, an Algonquian word meaning prostitute, a word used both by Indians and whites to refer to Indian women. Her name itself was spelled and pronounced several different ways. The spelling commonly used today has its roots in Hidatsa language and means bird woman.
Not long after leaving Fort Mandan in April 1805, Sacagawea proved her worth. She dove into the Missouri and saved valuable papers, supplies, instruments, and books after her husband nearly capsized the pirogue he was piloting. She survived a near-fatal illness a month later. On July 29, 1805, she, the baby, her husband, and Clark nearly drowned in a flash flood. A couple of weeks later Lewis reported that Clark severely reprimanded Charbonneau for beating his wife, which had been a frequent occurrence.
Sacagawea was held in higher regard after helping the Corps of Discovery acquire horses from her native Shoshones, who were now led by her brother, Cameahwait. She had overheard a Shoshone plot to leave the Corps empty-handed. She got word to the captains through Charbonneau before the Indians could carry it out. The captains were angry that Charbonneau had delayed passing on this information. They ended up giving Sacagawea a good horse for the trip through the Rockies and left Charbonneau to walk behind.
She helped the Corps survive during the trip through the Rockies as she dug for roots and showed the men how to subsist on them.
At the Pacific Sacagawea was allowed to join the rest of the party in voting on a campsite for the winter. She also was one of the first to see the ocean, demanding to join the first party to see the shoreline, where a whale was beached. As Lewis wrote, she "had traveled a long way to see the great waters, and that now that monstrous fish was also to be seen, she thought it very hard" if she was not selected among the first group.
The Mysterious End
On the return trip Sacagawea and Charbonneau left the Corps at a Hidatsa village. At this point the history of Sacagawea becomes much cloudier. It is believed that she might have accompanied Charbonneau to St. Louis for a short time before he decided to return to trapping up the Missouri. An 1811 journal entry puts her and Charbonneau at Fort Manuel Lisa trading post. An entry the next year on Dec. 20 recorded that "the wife of Charbonneau, Snake Squaw, died of putrid fever." The entry said she was about 25 and "had left a fine infant girl."
By this time, Pomp had already been entrusted to Capt. Clark. Court records in St. Louis report that on Aug. 12, 1813, Clark formally became the guardian of both Pomp and the girl, Lisette. In Clark's notes from 1825-1826, he lists Sacagawea as dead.
However, Shoshone oral legend has it that she returned to the Shoshones and died on a reservation in 1884. More evidence than not supports that the old woman on the reservation was not the Sacagawea of Lewis and Clark fame.