If you're unfamiliar with the history of the Donner Party it's a fascinating, if gruesome, read. Of the 83 members of the Donner Party who were trapped in the mountains, 45 survived to reach California. Some became quite successful there.

There were 90 wagons in the train and they were trying a newly conceived route to California that obviously didn't pan out well.

Imagine taking a wrong turn in the wilderness and finding that you've led 90 wagons into hard terrain and deep woods. They were at times literally having to cut trees down to clear a path through dense woods for miles and miles. Horrible, slow going, and hard work.