Can I ask what the need for speed is? It's really not worth it to stress over getting to an ADR in under 10 mins. Most of us hate spending too much time getting from point A to point B. But, at WDW, it's sometimes part of the fun. I would take the boat and make that part of the fun! It's a great way to get around, especially for little ones. I would leave MK about an hour prior to ADR time. If you run late, they'll hold the time for you.