Hi!
I'm pretty sure there's an "official schedule" somewhere, that should give a general point as to what to expect.
But at this time of the year, Disney World Transportation start well before the parks open, here it might be useful to check EMH for each park of course.
And throughout the whole day all transportation goes from A to B on their designated route. Let's people off and let people on. Then off back to point A again. And so on... Very rarely do transportation need to wait between departures, and guests seldom wait for long at their start and stop. Disney runs these services continously throughout the whole day and evening. And approx up to one and a half hour to two hours after park closing, as the official guidelines.
But trust me, Disney will not let guests be stranded anywhere!
So as traffic start to round off the routes in accordance to the number of guests waiting, they have bundled resort stops for one or several routes until the waiting areas are confirmed empty.
We were really late out from AK one EMH evening, I mean like crazy late lingering for the last evening on that trip.
The bus stop was more or less deserted when we finally got out. But a CM checked on the radio what was available, and we got to share a bus with guests to other resorts, until our came up as closest on the route. The driver did a short detour and dropped us off at our resort, then proceeded to the end stop of that bus route.
So it's Ohana all the way - The Disney World Family let no one gets left behind!
We had some issues with refurbishment schedules the last time we were there and the people at the desk having no idea what was up. 
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