8:05am at Crystal Palace with MK opening at 9:00am on Monday. We went to the bus stop at 7:15 to watch the MK bus just pulling away. The next one came at 7:48. We saw 5 AK, 6 HS and tons of Epcot buses while we waite(and the crowd built).
In hindsight, I would have taken the boat over to the Contemporary at 7:15and just walked to MK - or transferred to the monorail (or just waited for the boat directly to MK). We were obviously late for our reservation, but had no problems getting our table quickly.
This past week the Epcot buses to the park were running quickly. MK - not so much, but the boats were great (about every ten minutes).
(One morning we had to be at the Grand Floridian at 8:15 - we took the Contemporary boat and transferred onto the Monorail without any problems.)