One suggestion...
on the way into Epcot, where you pay for admission, make sure you get a copy of the day's activity times in each country. Each country has dances, musical engagements, drama and other enactments that really enhance the visit. If you time it right and keep up a decent pace, you can make it through all the countries getting to see the timed activities they have going on making the price of admission more worthwhile. When I was at Epcot 2 years ago there were folks who hadn't received the schedule when they entered so they were unaware of the events and missed out.
Also, we thought the food in a few of the countries was quite good, so it's worth enjoying some snacks or meals as you go along.