The word "then" is used incorrectly in the sentence provided. The correct word that should be used in this context is "than."
Here's the corrected sentence:
"Lindsey loves the outdoors so much that she would rather go camping than stay in a fancy hotel."
Explanation:
1. "Then" is used to indicate time sequence or what happens next, while "than" is used in making comparisons.
2. In this sentence, the intention is to compare Lindsey's preference for camping with staying in a fancy hotel, so "than" should be used to show the comparison between the two options.
3. By using "than," the sentence conveys Lindsey's preference for camping over staying in a fancy hotel in a grammatically correct manner.