I personally have not done this, but we seriously considered doing it prior to our last trip to avoid putting those miles (2600 miles round trip from Wisconsin) on one of our cars. (We ended up getting a great rate to fly Southwest after they started flying out of Milwaukee, so we didn't have to go this route.) But my plan was to rent a car in Wisconsin, drive it down to Disney. Drop it off once I got down there, and then rent a car for the drive back, thus saving us the rental fees for the week that we'd be using Disney transportation. Although now that I think about it, I wonder how much more they'd charge for a 1-way rental vs. a round trip rental and if that difference would offset us saving that week's worth of rental fees.