"Questions of Travel" seems to be a little afraid of nature. There's actually not that much nature per se in the poem. (Let's be honest: much of the poem is about a gas station, which is weird.) But the poem begins with a nature-ific bang—we are thrown suddenly into ominous waterfalls that threaten to submerge mountains. It's this fear (that the waterfalls are dangerous) that sets all of the speaker's philosophical mediations on travel itself in motion. So, we think that nature merits a pretty close look in "Questions of Travel."
The speaker is right to be scared of the waterfalls; a rushing waterfall is a scary thing. And people shouldn't go see things that are scary.
The speaker is acting like a scaredy-cat at the sight of the waterfalls. She's not in any danger; it's her imagination that causes her problems. So traveling is a good solution. Don't leave things up to the imagination; go see it for yourself.