Craig, thanks for your help. I wasn't aware of Draggable, and I have been working on implementing that. It has some features that I was wanting anyway, like momentum. I have updated the Codepen with Draggable and tried to delete a bunch of stuff that wasn't applicable to my issue. If you are tired of helping me with this, please just say so :P.
If you scroll with a mouse wheel, the scrolling and parallax works great and is nice and smooth. When I add Draggable to the .timeline_wrap class, it won't scroll on click. Same result if Draggable is added o the body. I have also tried the different drag "types". Some don't do anything, like "scroll" and "scrollTop". If I attach draggable to the body with "type: y", it works, but I lose my parallax. If I attach it to the ".timeline_wrap" with "type: y", it scrolls the page, and the parallax works, but it's no longer smooth. Seems like no matter what I do, I fix one thing, break another. And I apologize, I don't know if this is a Greensock, ScrollMagic, CSS issue, or a combo of all so I keep bugging you about it. Thanks for any ideas!