We hear that young people don't know much about history. Perhaps their teachers should have them read the works of Stephen Ambrose, whose Undaunted Courage: Meriwether Lewis, Thomas Jefferson and the Opening of the American West is what they used to call a page-turner. But it is also essential and well documented history.
Jefferson was a visionary (a word that usually makes me cringe). The Louisiana purchase was a good idea. So was the thought that there might be a water route to the Pacific via the Missouri and Columbia Rivers -- not found, to the great disappointment of all involved. So also was the choice of Meriwether Lewis to assemble the group of explorers and lead them through unknown territory and back. Jefferson was also wise to have Lewis move into the White House as part of his preparation so that the two men could share all that Jefferson knew of the relevant geography, navigation, natural life, etc. Lewis was instructed to bring back information as well as examples of plant and animal life. There was no thought to finding gold or silver. Ambrose calls all this emblematic of the "American enlightenment."
We see that trade and new trade routes were seen for their fundamental value and importance (unlike many commentators today). We learn that Indians who had never seen white men were ready and eager to trade. Aside from one episode, whites and Indians were able to avoid confrontation and violence. This in spite of their mutual strangeness and no common language.
Yes, Lewis and his men referred to the Indians as "savages". Lewis and others of the expedition saw that it was natural to own black slaves. They were men of their time. But when major route choice decision time came, "[t]his was the first vote ever held in the Pacific Northwest. It was the first time in American history that a black slave had voted, the first time a woman had voted" (p. 316).
Lewis came to a bad ending. He was a much better explorer than a politician. Jefferson's great failing was appointing him Governor of the Louisiana territory on his return from the expedition. Lewis and Clark failed to follow up and get their valuable journals published. That was left to others. "... [T]he journals he [Lewis] wrote are among his greatest achievements and constitute a priceless gift to the American people, all thanks, apparently, to lessons learned from Mr. Jefferson during his two years of intimate contact with the president in in his house" (p. 67). Read the book.