As it stands, it makes no sense to say that visitors more than made up for the stress. While it's possible to interpret it in this way it's highly improbable.
It's far more likely that the sentence is simply poorly constructed (and it is, regardless of anything else). This is also seen by the awkward construction in the final part of the sentence that ties into that confusing use of visitors.
I would make a few edits, including correcting this main issue. Note that, in my version, I add a phrase in square brackets only to aid comprehension, not because the sentence needs it.
✘ While traveling to the spa's remote location could be hectic, visitors to the spa more than made up for the stress by unwinding in a supremely Pacific environment.
✔ Although travel to the spa's remote location could be hectic, the spa itself more than made up for any stress [in getting there] by allowing visitors to unwind in a supremely Pacific environment.
Note, too, that this is a past-tense statement. If it means to describe something in the present, then it should be can be hectic and more than makes up.