ON SENT (additional settings)

Maybe try the following:

on_sent_ok: "ga('send', 'event', 'Contact Form', 'Sent'); location='http://www.driftstories.com/thank-you';"

You can also check your source code and/or use Tag Assistant chrome extension to check if the goal is added correctly instead of waiting to see if it shows up in GA 24-48 hours later.

Also, you can use on_submit hook and use a separate goal. That way you can troubleshoot onclick events vs on sent confirmed events.