I'd vote for bus to MK and then boat to FW. We did this for Hoop De Doo when staying at OKW last April. The boat ride is lovely and relaxing and you get off in the right area for both HDD and Mickey's Backyard BBQ. It added to the experience. There were buses waiting after HDD to go back to the resort. We did stop at Port Orleans - but it wasn't bad. If there are no resort buses waiting after the BBQ, I'd just head back to MK and take the bus from there. If you're lucky, maybe you'll be on the water at the same time as the Electrical Water Pageant or Wishes.