Thanks for the input everyone. Epcot is going to be a definite must-do. Also, I would love to ride a few of the MK rides that we don't usually get to ride when we have the kids with us.
It has been so hard to decide but I think we'll start at MGM since this is one park that we really don't spend much time at with the kids. It's not my favorite park but there are a few things I'd like to see and then we can make our way to Epcot. Depending on how much we get to see at Epcot the night before, we can either return to Epcot the next day and, if there's time, zip over to MK or just go straight to MK.
We're going to have to play it by ear somewhat because, while we want to do as much as we can, we also don't want to feel too rushed. Got to save some time for eating too (which is a luxury in itself when the kids are not there). I think we will make our way over to the Boardwalk after the parks close, maybe stopping in at Jellyrolls for a bit if we're not too wiped out.