Disney Magical Express if you were staying onsite, Mears transportation if not staying at a Disney hotel. Why not just drive to the airport and return your rental car at the airport.
I was able to snag a convertible for two weeks for only $200 incl. all taxes, so I don't want to change the reservation for MCO drop off as it will change the rate drastically. We are staying on site the first night we arrive so I will use DME, but after that we are heading to our timeshare units.