Tracking a Referral Page

We're launching a new version of our site that, instead of having a form on every page, just has a button on every page that links to the Quote Request page. I want to track the page that refers users to the Quote Request page and be able to report on the high level metrics of the pages that refer the most people to the Quote page. It's not necessarily the landing page because they might visit several pages beforehand, and I find that the Original Referrer field will sometimes capture the previous page the lead was on, but other times it will capture the outside page the lead was on that referred them to my website. Or maybe I'm mistaken on that? I know I could use an URL parameter on each button on each page, but that might end up getting hard to manage. Is there a custom script I could use to capture the most recent referral page? Or is this something Marketo can capture natively?