answer: No Sacagawea wasn't very essential to the expedition's success. Without or with her, I they could have still made it. The baby she had with her was slowing them down, and kept the journey harder for these two young men. They ended up leaving her at the village because it was to dangerous. After that the two young men flourished with success. They got done in the matters on 2 1/2 years. With her and her baby it would have made it harder. Her people did help with the transportation, but even without the horses they would have made it eventually. This is my response arguing whether Sacagawea was important to this success.
Explanation: This is just my opinion on this story.
But this should help.