We always go to an Epcot resteraunt the first night. The last time we went my DD was 6. After arriving in Orlando, we go to the hotel (on-site), go swimming to get active again after the plane trip, take a nap and then head over to Epcot for reservations at 7 or 7:30. There's no rushing, if we are early then we see some of the park. After dinner we walk leisurely back to the front of Epcot and usually are in place for the fireworks. Then head back to the hotel. In Oct, the crowds are not that bad. This is our way of easing into the theme park experience.
But it's the nap that allows us to do it. I am exhausted after the trip to Orlando and if you let the kids sleep longer than usual (which they usual do because it seems like you've been up forever) they will be able to stay up a little later. They sleep well that night and then it's up bright and early with a Mickey wake-up call.
Hope this helps,
JC