Pitch A Tent Kauai https://www.pitchatentkauai.com/
I emailed them and then communication by text message. I explained my dilemma and they were able to hook me up with what I needed, I could even pick it up at 6:00 am on my way to the trailhead. They have a lot of gear for rent and I will change my future hiking plans with the help of Pitch A Tent Kauai.
Google Review: https://goo.gl/maps/QUR5TC5dQiZPqi26A
