Final answer:
The two words used incorrectly are 'adverse' and 'among'. 'Adverse' should be replaced with 'averse', and 'among' should be replaced with 'between'.
Step-by-step explanation:
The two words used incorrectly in the sentence are:
1. Adverse should be replaced with averse. Averse means having a strong feeling of opposition or dislike towards something.
2. Among should be replaced with between. We use between when referring to two distinct entities or people.
So, the correct sentence would be:
If Rick isn't averse to traveling for a bit longer, he could save money by taking the train between Seattle and Portland instead of flying.
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