I have an EPCOT tour scheduled and staying at BW this Dec. I contacted disney and got this reply
There should be Cast Members at the International Gateway entrance to allow guests in to Epcot® prior to opening in order to make it to the early morning tours at the park. Guest Relations at the International Gateway does open up an hour prior to the earliest park opening, however there should be Cast Members and Security there by 7:45 AM. Please let them know that you have a tour scheduled for that morning, along with the confirmation number you were given, and they will make sure that you get to the meeting spot for your tour in time to check in.