Getting from the airport to Walt Disney World can be very simple for on site guests for one main reason; The Magical Express.
Other options include Mears Taxi, though I find this a very expensive option
Uber, you can hail an Uber to MCO to collect you and bring you to Disney World or any resort nearby.
There is no train option… this was discussed at one stage to build a high speed rail line between Disney World and the airport at MCO, but was opposed by other theme parks in the area. Perhaps in the future we’ll get an easy link from the airport to the most magical place on earth!
Disney From Ireland 