Also, if 1 park has EMH, will the bus run early for all parks, or just the park with EMH. Thanks in advance!
Second question first (because it influences the other question). I'm not a rope drop person, so this information is based on answers provided bus drivers. I specifically asked about this and was told the following by two different bus drivers.
Disney Springs Hotels buses go to parks that are open or about to open. So, if there is an early Extra Magic Hour (example 7am), the first bus leaves at 6am. If all the other theme parks do not open until 9am, that bus will not go anywhere else. Instead, it will return to a staging area (since there won't be any guests to pick-up) and wait for the next trip on the schedule.
If we get on the first bus, assuming is 8am for a 9am opening, when can we expect to arrive at the parks?
The answer to this question is a bit complicated depending upon when theme parks open.
Scenario 1: Early Extra Magic Hours - First Park to Open
As described above, if there are early Extra Magic Hours happening, there shouldn't be any detours for the first bus going to the first park that opens. You will head directly to the park (or Transportation and Ticket Center for Magic Kingdom). Travel times vary, but you should arrive about 20 to 25 minutes after leaving Hotel Plaza Blvd where all the Disney Springs Hotels are located.
Scenario 2: Early Extra Magic Hours - Second Park to Open
On some dates, there are two theme parks set to host early Extra Magic Hours. For example, Disney's Hollywood Studios will open at 6am and Magic Kingdom opens at 7am. At this point, it is unclear how the buses from the Disney Springs Hotels will operate. They might use two buses, one going to each theme park. In that case, you should arrive about 20 to 25 minutes later.
Or, they might combine both routes on a single bus. If that's how it works, you'd would not arrive at the second theme park on the route until 40 or 45 minutes after leaving Hotel Plaza Blvd.
Scenario 3: One Park with "Regular" Morning Extra Magic Hours
In this scenario, I'm defining "regular" Extra Magic Hours as opening 1 hour early. Example: One theme park opens at 8am and the rest at 9am. If you're heading to the park with Extra Magic Hours on the first bus, you'll arrive 20 to 25 minutes later.
However, if you're heading to the second theme park on a given route, you may have to take a detour to another park. That means that even though you are on the first bus of the day to that park, it still might take 40 to 45 minutes to arrive.
Scenario 4: No Morning Extra Magic Hours
Here, all parks essentially open at the same time. That means 20/25 minutes to the first park and 40/45 minutes to reach the second park.
Because the combinations of which two theme parks are grouped together can vary, you really won't know until that morning whether you will be lucky and head directly to your destination or if you'll have to take the detour.
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* IMPORTANT: Everything might change when Star Wars: Galaxy's Edge opens. If there are hundreds of people staying at the Disney Springs Hotels all going to Disney's Hollywood Studios, the bus operate (Mears Transportation) might alter the way they run the buses.