I know that more and more people are complaining about the buses, and they have every right to.
Even though extensively spread out, there are still core areas in the resort that are relatively compact; MK/Resorts, DHS/Epcot/Resorts, Downtown Disney/Resorts, and hotel row near Crossroads. Run park to park express routes adjacent to these routes.
Rail routes are straightforward to design serving these core areas. A circular route can service the outlying areas. Need to add value and make money from this? Add some profitable destinations themed with each resort and the resort tour becomes its own attraction.
With the rail traffic as a feeder, consider finally building Progress city. It becomes the light rail hub and a separately themed guest and business destination. There is even a prime place to put it - west of the junction of Epcot and World drives. Good rail access to all 4 parks. Good road access with Epcot Drive, World Drive, and Western Way.
A new development of similar shape and import is happening on the other side of the world, in China: themed industrial parks and cities. A story worth looking into. Walt's spirit lives on in the world's most dynamic economy, no longer ours.
Bob JacobsonPhD, Urban Planning, UCLA