From North Alabama it's 670 miles from our driveway to the sign on World Drive
It usually takes us 10 1/2 - 12 hours depending on who's with us.
(I've driven it solo in 9 1/2 hours, 1 stop for gas/restroom in Valdosta when the tank ran dry, approximately 75 mph the entire way)
Our biggest problem is no easy access over to I-75. We either have to take back roads down to I-20 east of B'ham or take I-65 through Birmingham, then I-20 East, or take I-65, then back roads down to I-10, or take US 72E all the way to Chattanooga, then I-75. If the Memphis/Atlanta Freeway EVER gets built, that will probably take 2 hours off our trip!!!
However with our new direct flights to Orlando that we can usually get for less than $150, we usually fly. Only have to be at our airport about an hour early, then a 90 minute flight. Now coming back home is another story because of the long lines at MCO.
Our worst trip home was the Sunday after Thanksgiving 2002, never broke 40 MPH on I-75N. Took us 14 hours from Ocala to home.