You can also do a one day rental when you fly in and drop off car on Disney grounds.
One company, I think Budget, has a facility at Doubletree Hotel in Downtown Disney. Alamo or National has a pick up at the Swan or Dolphin.
You can get a car a Sanford and stop for snacks/groceries/whatever then take suitcases to your hotel. The next morning take car to drop off then take their bus to park.
Book another rental for one day when you fly out.
Usually one day rentals are $20-$30.
It is not a bad drive. Take the 417 tollway. There are a lot of police checking speed, so do not speed.