We knew better than to attempt a MK visit in 2000. During our bus trip from ASMo to Epcot, I heard an announcement on the bus two-way, that no more buses were to enter MK, it was full. This was about 10:30 in the morning. We got to Epcot, and passed the gates and turned around and spent the next few hours at the pool.
We returned to Epcot later that day to see the parade, and got a wonderful spot at the end of the route, which was fairly close to the area that we planned to watch Illuminations from. The other bad thing was the fact that this happened around 6:00 P.M. and there were already people staking out their place for the fireworks.
I would recommend Epcot, just be ready for the heat, with plenty of water, a book, or other timewaster.